There is still no official reply on what dev thinks the definition of "femboy" is.
A lot of people disagree on what such obscure words mean and as such it is not clearly communicating what fetishes are found in this game.
Does billy have a penis? does billy have a vagina? does billy have both?
Does billy have boobs or not?
was billy born with penis/vagina/boobs or did billy's body get modified. (if billy's boobs or genitals were surgically or hormonal modified then billy is trans, not a femboy)
As for editing billy's chest to be flat... are you changing billy to make it so billy no longer has female boobs? Or are you saying that billy was not supposed to have boobs and you messed up the art previously?