1. I mean, ideally, it would all be written in a way where everything over the course of the game ends up mattering for that specific route, and then the ending is the ideal solution the experiment set out to do. That way you can pair Dave up with whoever you want, and everyone benefits from the character development and growth. There's no way to do it if you go back to a start that's both before anything happened and after everything has happened. And yeah, I understand that everything *does* matter, and you don't want the mansion vacation to happen if it doesn't need to happen. So, fixing Roswell means that no one has to go there in the future timelines/loops and so it's a problem that simply can't be reconciled with how the game is now. It would take heavy adjusting, probably far too involved at this point and with how long you've spent on it already, sooo... idk.
2. It still just feels like it's something that happens "just because" to block anyone from fixing him after the start. If Roswell knows about things and the potential for things then his actions don't make sense to me. And if he can learn from his actions in the same way, can't he just learn *not* to do that thing?
I can't really comment on the epilogues situation since, like I said, I haven't played any of them. Maybe it does make things better. Also, I'm not trying to be disrespectful in my responses either. I get this is picking at something you've spent a lot of time and effort on. You've worked it all out, you've already planned a sequel and have epilogues and all that stuff. You're gonna have people who think it's a genius move and you're gonna have people (like me) that just don't like it. I think it's fine, and I personally do love time loopy things. Zero Escape is in my top favorite game series. It's just a big sore point looking back on all the other routes and then the true ending being... what it is, and I know I keep pointing back to it but it's just the disappearance of the character development that really kills it for me.