If jestur really wants the incest debate to finally end, he is going to have to make some changes to the early game. It's not even about tiffany, the whole plot was developed to be incest from the beginning, and it shows. The MC has a lot of friends and acquaintances who are all the same age, all of them having only their mothers and not a single clue about their fathers, and then the MC travels back in time and gets to know every single one of their mothers at a young age, all of them single and messing around with the MC. So what's more logical?
1. The MC being the father of all of his friends, that he got all of the moms pregnant in the past while messing around with them and then disappeared since he stopped going back in time.
2. After MC disappeared from the past, they all found boyfriends at the same time, got pregnant the same year, and all their husbands either left or died.
Can you all see where the problem is? , jestur now has to work around a massive plot hole left by the removal of the incest, so even if you don't play with the mod, you are going to feel like something doesn't add up the more you play, so the debate will continue on and on with people asking about the mod, the tags, which one is canon, and so on.
There is one solution, but I think it would displease everyone: Jestur could make it so all of them did get pregnant from the same guy, just not the MC, so someone else got the harem in the past. Although this one would backfire if there are plans for threesomes with the present girls because now it would be incest again.