So having gone back and replayed this without the incest patch again, I've come to the conclusion that it doesn't need it. This honestly doesn't need to be a thing.
Jeanne is still basically your step mom, the idea of betrayal of family is still there, albeit it goes from betrayal as a mother to betrayal as a wife.
Lizzie and you grew up together, she is still basically your sister, especially in her own eyes. Anything developing between Brian and her will still be a massive conflict for her.
So... I'm torn. My old save file has the incest, the new one doesn't. I'm not sure which I really want to do in the future because I feel like RC will be crafting story around it in the future, and I feel like I'd missing out. Especially if Amie shows back up.