Ooooooh, sounds like a fun character!
EVA foam is tricky, and I can't claim to have any experience with it, but this video is pretty good:
https://www.youtube.com/watch?v=dN3NHy7AsqcThere are lots of EVA armor patterns out there. Etsy is a good place to look, and Simplicity has a funny boob armor pattern:
I don't know if you wear makeup, but contouring really helps with crossplay (it can only go so far though—I have far too many photos of me dressed as hysterically babyfaced men). You might want to look up drag tutorials too—try the term 'fishy' for more subtle ones though.
I look forward to seeing what you come up with!