A similar method to this might be good for that. Just make it in two parts, with closures at the sides
You could also just make a front chest piece, and attach/wear it over a bra bustier. I would definitely wear something under the armor, though, just in case it cracks/slips. For the bottoms a bathing suit pattern would work well. Wear a nude thong or if you want your legs to look smoother + some more coverage wear dancer tights under the bottoms.