An excellent chart showing this very subtle mechanic.
I wish you the best for finding the minimum "points", or necessary reactions for each character

That's a relief. Thanks. :)

All of these are optional. They just slightly change how the ending plays out. None of it screws you over.

I am playing this for the first time. I already restarted once because I found I made a big mistake. Now I just realised that I missed the Mina running away dialog because I was distracted and didn't realise until after saving that I was supposed to chase her down for it. Is missing 1 dialog going to screw me at all? I REALLY don't want to start over for a 3rd time...

I find it interesting that even if you completely pacify all of them, Elro's shadow (your brother who supposedly does everything to protect you), is the only one who still attacks you. Meanwhile, I think it only takes like one nice response to Royal in order to pacify him completely. I really like the game's portrayal of these very flawed characters and how hard (or even impossible) it is to redeem them.

This is why dying to mother brain in Metroid (NES) is so painful. If you save state at the beginning of mother brain's room, the fight is a joke and can be completed in 10 minutes. But if you play by the game's rules, upon death, you are reset to 30 health and whatever missiles you had when you died, so you have to go back and grind for potentially up to 20 minutes just to get your resources back. 3 attempts with save states takes up 5 minutes of your time. 3 attempts by the game's rules could take well over an hour. the length of time you have to wait between individual attempts matters a great deal, as even a few seconds can waste hours of time in the long run.

for example, in IWBTG, an average playthrough might experience 500-1000 deaths, if not more. If there was a mandatory 10 second waiting time between attempts, like say you had to sit through the full game over music before it lets you press R, that's 10,000 extra seconds added to the playthrough. Almost 3 hours.

"A few seconds" adds up very quickly over a lot of attempts.

why do you care about it so much braden? its a few seconds-

When you skip a cutscene, it'll autoselect the first reply (not necessarily the worst). What I was asking is what happens if you skip a cutscene *after* manually selecting a dialogue option, because that isn't made clear anywhere, and being able to do that would cut the pre-agent-white fight cutscene a lot shorter.