First of all, before you get mad that I'm trying to prove something, just know I'm treating this as a mental exercise. Just kind of toying with how to make it all gel. You've clearly read more than me, and I'm just playing around seeing if ideas could work. I like doing that, as pointless as it is. Secondly, I'm hopped up on a sleeping pill that's juuuust starting to work. So this may get dumb.
Like you said, Creation Myths are myths told by that person in a desert. And I think World Of are "based" on Aughra's notes. So neither is an objective view of events, that leaves wiggle for... something. She could be leaving her son out of her version just because of how personal that was.
But to maybe reconcile to the two stories, maybe it happened like: None of them had conquered their shitty sides, but they still wanted to attempt to get home. One scientist was trying to burn their dark side away, knowing they wouldn't be allowed back still with that in them. Raunip tricks him/fucks up the experiment, it sends out a wave of energy that effects all 18, and they split.
The machine would still get them home, but rather than being the literal tool it would be the thing which lets them stay.
I'm convinced I didn't resolved a few details that I had resolved while eating not 20 minutes ago and everything is getting fuzzy. That pill is doing it's shit.
Okay man, have a nice night.