That's up to you. I'd have to resize everything eventually for the Comixology ver, because the page itself would be in A4 format (2480 x 3508). The main thing is that it has to be in 300dpi or higher, but other than that go nuts.
Ah, the comment I dreaded the most. I'd go moderately, but, if more people want to do things like that I can always make a separate gallery, like an "After Dark Edition". If there isn't enough people for it I can post the censored version and try and find some other platforms that would include every ones work in one gallery.
More like fanart or other artists take on the character. It doesn't have to be erotic or sexual in any way. I used the term "pin-ups" because that's what they used to call the gallery that you'd see at the back pages of comics. Basically, anything where people can go wild with their imagination and style.