I don't think your plan is terrible (it's a reasonable workaround of the system not allowing us to close duplicates against unanswered questions), but I think I would generally proceed in a different way (as suggested by muru).

1. Choose the best _{(subjective, but you can try to judge which will be the best to close the others against - clearest, most general, etc)} question, or if some/all of the questions are old, the one whose asker seems the most active, and post your answer there.
2. Comment on all the other questions linking to your answer. Note that the notification we receive when someone answers our question looks the same as the one we get when someone comments on our post, so I don't think it's less likely to get a click if the OP is paying any attention at all to their question/notifications.

This also makes it more likely that questions will be linked by others if you forget or aren't able to do it yourself - if you aren't active on the site, one of your multiple answers getting upvoted won't let anyone else know that other questions can now be closed against this one. 3. If your answer gets upvoted/accepted, flag/vote to close all the other questions.¹ 4. If you get no upvotes/accept, but one of the other OPs comments that your answer worked for them (but they have no reputation to upvote), you could re-post your answer to their question where it's more likely to get an upvote (since others may notice the comments) or at least an accept. Flag/vote to close the other questions and delete your original answer if you really want to.¹

It's not uncommon to get accepts/upvotes weeks or months after posting an answer. If you're worried that you might forget to flag/vote to close the other questions or you might not be using the site when you do finally get an accept/upvote, you can put some links to the similar questions in your answer to help others find them.

The system will allow you to post duplicate answers, but if they are exactly identical, they will be automatically flagged for moderator attention. I doubt that in the case you describe there would be any negative result of this - in fact it might be a good thing, because mods generally know the site better than other users and might be aware of another question of which all the ones you answered are duplicates.

I'd say it's more ethical to answer questions than not answer questions because you're worried about site management issues. If you have a solution, it will be most helpful of you to share it. If you really feel that in some particular case, the best way to do that is to post it more than once (keeping in mind that we try to avoid duplicating content where possible so that resources for the same issue are gathered in one place), then go ahead, and let others fix the site management situation if they know that side of Ask Ubuntu participation better.

¹ _{Here I am talking about cases where the questions are actually duplicates. If the questions are not duplicates, but merely closely related, you may find than posting similar answers tailored to the details of the question is appropriate. It may even (very rarely) be the case that the same answer applies to questions that are not really duplicates, in which case, you should feel free to post the same answer to each of them.}

I don't think your plan is terrible (it's a reasonable workaround of the system not allowing us to close duplicates against unanswered questions), but I think I would generally proceed in a different way (as suggested by muru).

1. Choose the best _{(subjective, but you can try to judge which will be the best to close the others against - clearest, most general, etc)} question, or if some/all of the questions are old, the one whose asker seems the most active, and post your answer there.
2. Comment on all the other questions linking to your answer. Note that the notification we receive when someone answers our question looks the same as the one we get when someone comments on our post, so I don't think it's less likely to get a click if the OP is paying any attention at all to their question/notifications.

This also makes it more likely that questions will be linked by others if you forget or aren't able to do it yourself - if you aren't active on the site, nobody (except the voter) will immediately notice one of your multiple answers getting upvoted, and if the questions aren't linked, people won't know that other questions can now be closed against this one. 3. If your answer gets upvoted/accepted, flag/vote to close all the other questions.¹ 4. If you get no upvotes/accept, but one of the other OPs comments that your answer worked for them (but they have no reputation to upvote), you could re-post your answer to their question where it's more likely to get an upvote (since others may notice the comments) or at least an accept. Flag/vote to close the other questions and delete your original answer if you really want to.¹

It's not uncommon to get accepts/upvotes weeks or months after posting an answer. If you're worried that you might forget to flag/vote to close the other questions or you might not be using the site when you do finally get an accept/upvote, you can put some links to the similar questions in your answer to help others find them.

The system will allow you to post duplicate answers, but if they are exactly identical, they will be automatically flagged for moderator attention. I doubt that in the case you describe there would be any negative result of this - in fact it might be a good thing, because mods generally know the site better than other users and might be aware of another question of which all the ones you answered are duplicates.

I'd say it's more ethical to answer questions than not answer questions because you're worried about site management issues. If you have a solution, it will be most helpful of you to share it. If you really feel that in some particular case, the best way to do that is to post it more than once (keeping in mind that we try to avoid duplicating content where possible so that resources for the same issue are gathered in one place), then go ahead, and let others fix the site management situation if they know that side of Ask Ubuntu participation better.

¹ _{Here I am talking about cases where the questions are actually duplicates. If the questions are not duplicates, but merely closely related, you may find that posting similar answers tailored to the details of the question is appropriate. It may even (very rarely) be the case that the exact same answer applies to questions that are not really duplicates, in which case, you should feel free to post the same answer to each of them.}

I don't think your plan is terrible (it's a reasonable workaround of the system not allowing us to close duplicates against unanswered questions), but I think I would generally proceed in a different way (as suggested by muru).

1. Choose the best _{(subjective, but I you can judge which will be the best to close the others against - clearest, most general, etc)} question, or if some/all of the questions are old, the one whose asker seems the most active, and post your answer there.
2. Comment on all the other questions linking to your answer. Note that the notification we receive when someone answers our question looks the same as the one we get when someone comments on our post, so I don't think it's less likely to get a click if the OP is paying any attention at all to their question/notifications.

This also makes it more likely that questions will be linked by others if you forget or aren't able to do it yourself - if you aren't active on the site, one of your multiple answers getting upvoted won't let anyone else know that other questions can now be closed against this one. 3. If your answer gets upvoted/accepted, flag/vote to close all the other questions.¹ 4. If you get no upvotes/accept, but one of the other OPs comments that your answer worked for them (but they have no reputation to upvote), you could re-post your answer to their question where it's more likely to get an upvote (since others may notice the comments) or at least an accept. Flag/vote to close the other questions and delete your original answer if you really want to.¹

It's not uncommon to get accepts/upvotes weeks or months after posting an answer. If you're worried that you might forget to flag/vote to close the other questions or you might not be using the site when you do finally get an accept/upvote, you can put some links to the similar questions in your answer to help others find them.

The system will allow you to post duplicate answers, but if they are exactly identical, they will be automatically flagged for moderator attention. I doubt that in the case you describe there would be any negative result of this - in fact it might be a good thing, because mods generally know the site better than other users and might be aware of another question of which all the ones you answered are duplicates.

I'd say it's more ethical to answer questions than not answer questions because you're worried about site management issues. If you have a solution, it will be most helpful of you to share it. If you really feel that in some particular case, the best way to do that is to post it more than once (keeping in mind that we try to avoid duplicating content where possible so that resources for the same issue are gathered in one place), then go ahead, and let others fix the site management situation if they know that side of Ask Ubuntu participation better.

¹ _{Here I am talking about cases where the questions are actually duplicates. If the questions are not duplicates, but merely closely related, you may find than posting similar answers tailored to the details of the question is appropriate. It may even (very rarely) be the case that the same answer applies to questions that are not really duplicates, in which case, you should feel free to post the same answer to each of them.}

I don't think your plan is terrible (it's a reasonable workaround of the system not allowing us to close duplicates against unanswered questions), but I think I would generally proceed in a different way (as suggested by muru).

1. Choose the best _{(subjective, but you can try to judge which will be the best to close the others against - clearest, most general, etc)} question, or if some/all of the questions are old, the one whose asker seems the most active, and post your answer there.
2. Comment on all the other questions linking to your answer. Note that the notification we receive when someone answers our question looks the same as the one we get when someone comments on our post, so I don't think it's less likely to get a click if the OP is paying any attention at all to their question/notifications.

This also makes it more likely that questions will be linked by others if you forget or aren't able to do it yourself - if you aren't active on the site, one of your multiple answers getting upvoted won't let anyone else know that other questions can now be closed against this one. 3. If your answer gets upvoted/accepted, flag/vote to close all the other questions.¹ 4. If you get no upvotes/accept, but one of the other OPs comments that your answer worked for them (but they have no reputation to upvote), you could re-post your answer to their question where it's more likely to get an upvote (since others may notice the comments) or at least an accept. Flag/vote to close the other questions and delete your original answer if you really want to.¹

It's not uncommon to get accepts/upvotes weeks or months after posting an answer. If you're worried that you might forget to flag/vote to close the other questions or you might not be using the site when you do finally get an accept/upvote, you can put some links to the similar questions in your answer to help others find them.

The system will allow you to post duplicate answers, but if they are exactly identical, they will be automatically flagged for moderator attention. I doubt that in the case you describe there would be any negative result of this - in fact it might be a good thing, because mods generally know the site better than other users and might be aware of another question of which all the ones you answered are duplicates.

I'd say it's more ethical to answer questions than not answer questions because you're worried about site management issues. If you have a solution, it will be most helpful of you to share it. If you really feel that in some particular case, the best way to do that is to post it more than once (keeping in mind that we try to avoid duplicating content where possible so that resources for the same issue are gathered in one place), then go ahead, and let others fix the site management situation if they know that side of Ask Ubuntu participation better.

¹ _{Here I am talking about cases where the questions are actually duplicates. If the questions are not duplicates, but merely closely related, you may find than posting similar answers tailored to the details of the question is appropriate. It may even (very rarely) be the case that the same answer applies to questions that are not really duplicates, in which case, you should feel free to post the same answer to each of them.}