I've noticed that ever since the removal of the random lost encounters there are no more ways to obtain certain species' parts. There's no option to spar with Abel to get feline traits when using the mimic ability or the same thing with the minotaur after he joins you. There's also no way of getting Behemoth traits either since Ethrex will give you demon traits. I find it really cool that shark traits can be acquired from Leviathan though!
Perhaps something can be added to gain those traits and combine as you please. Some people might want to combine feline with behemoth or something, but they wouldn't be able to as of now. Maybe the villagers you corrupt could be turned into the various species of which you can mimic traits from. Or maybe reaching the abomination perk allows you to fully pick and choose your traits, or a higher level of it like "Mutation Mastery" or "Mimic Mastery" or something like that.
Of course I don't expect art to be drawn of every variation as that would be too much, but perhaps have a sort of silhouette depicting the parts? Have a few stages of muscle mass from skinny to huge muscles and have different shapes of them to show people roughly what their character's shadow looks like. Maybe with the description, silhouettes of the mentioned parts could be shown to depict the shape, maybe with the added purple in case of the demon parts.
These are just ideas, so take from them whatever you think would fit and would be doable. Keep up the great work!