So, I just have a little question about the cosplay contest.

Are we allowed to enter only once? Or even only once per category? (CW / non-CW)

Or could we just ... go nuts?

I don't know about entering for each category, but I'm pretty sure you can only enter one. You can only have one entry, but you are able to change to another entry later.

You can only enter one HA, one category.