It is just my opinion, but 10 slots are too much for us to celebrate 10th anniversary. What about updating mobile page of the wikia? Also we don't have to hurry about this. Even in Kamachi's 10th anniversary, they had spent whole year to celebrate it.
For megapoll idea, why don't you separate OT/NT/SS, choose top 5 of each poll, and take run-off voting. For mobile main page of wikia, can you update featured article?