Can a true I patch work for this game??
short answer no. long answer is you would have to change a lot of the beginning story to make it incest. the shortest route I can see is you are adopted, the parents at the beginning are your adoptive parents, when the mom dies, your actual mom comes back into your life (her husband, your actual dad having died, which is a staple of any good incest game) and your real mom and adoptive dad hit it off and get married, but then the adoptive dad dies, leaving you with your real mom and real aunt/cousins.
I personally don't mind the stepcest, I know that's kind of contentious, and I haven't played through the game fully yet, but I feel the game is more focused on the mc and the trauma he is going through than pure incest content, so it'll be more story driven... how close am I
FF Digital ?