I regret to inform you that despite my efforts, I've been unable to locate the game's source code for modification. I spent several hours scouring various directories without success. Additionally, I reached out to the game's developer regarding access to the source code. Unfortunately, they informed me that they're unable to share it as he lacks the authority to distribute it, being not the main developer. Therefore, it seems unlikely that I'll be able to make the desired modifications.
I've also talk to him about possibly adding the ability to edit the percentage of futanari breed chance -
He mentioned that while it's an intriguing idea, it presents a challenge in terms of control. He explained that he originally designed the game with the principle of maximum simplicity in mind, which contrasts with the notion of implementing specific parameters for the futanari character.
Also about future updates for the game (Life with the Tribe), they won't be until he finishes the MFH (My Forest Home)