Followup questions: How well attested actually is this event? What are the agreed-upon facts about it?

This might be as much of a question for /r/askscience as it is for this sub.

while you are waiting, here is an informative previous thread

https://www.reddit.com/r/AskHistorians/comments/159osc/dancing_plague_of_1518_this_cant_be_real_can_it/