It's impossible,Mofu is futanari lover and he is an author specializing in futanari,you can know this from his previous works.The setting of this work is that all characters are futanaris.If some fetishes to be set optional, it may be executed,but setting futanari element to be optional is contrary to the theme of the game and it doesn't conform to the dev's idea.
And about what you said "similar game that doesn't have so many futa",you can play one of his past game named"Futaring",many characters in this game are not futa,or it should be said that many characters could be changed into futas in the later stage, or through some operations of the players,that's optional,I remember that only some of characters are inborn futanaris.