I am having the same problem xD, reply to me if you manage to get one of those.
i had a hard time with those too lol... there's a guide to how to get each ending in the artbook if you can afford throwing 5 bucks at the devs!
if not, i'm not sure what would be good advice for getting ending 2, but i think getting ending 8 takes a delicate balance of having cassidy believe the best of elowen/not dwell too much on her ~true nature~ while Also not completely giving up faith in alexander. at the "what's cassidy's final impression of elowen" choice i had all 4 options which had never happened before in my other playthroughs.
Oh dear, I spent another 2 hours yesterday trying to get those two missing endings... and I couldn't manage it. I've had all four options too and yet they did not make a difference.
It's nice to know that there's an artbook with a guide but right now it would be really irresponsible for me to spend money since I got sent home to be in lockdown without my paycheck :(
To the devs: you just released this and I'm already yearning for another game from you ;D