I think most, if not all kinks, have "sub-groups" of people who like it for different reasons or in specific ways, so it's not that easy to give a fit all answer and some incest fans won't like what you make even if you are not actually doing anything wrong. I mean, you can see it already here, how some people reply in a way like "this is the way, of course", but then someone else replies "actually...". So, I think first you really have to identify what do you want to do with your game/story. You do that by asking yourself why do you like the kink in the first place, and I'm assuming you want to make an incest game/story because you like the kink yourself. And then look for popular games or content you like, it will help put things in perspective before you even consider other people's feedback.
As an example, not meant to be an attack on that user or something like that, just in case, but someone mentioned needing to have characters with natural bodies. But if you look around, you see stuff like Urban Demons, the other game from the same dev but in a zombie apocalypse (can't remember the name of the dev or game right now), Demon Deals, Jackerman's content and a ton of other classic incest content with huge thick MILFs. I mean, I'd go as far as saying mom-son incest content tends to be linked with thick huge MILFs more often than not.
Asking for feedback is great, I'm in the middle of doing the same, but you need at least a base idea of what you want to make and references of popular games or content done with those so you can filter the feedback.
