Headcanons on the Caliborn ghost from the timeline where he died to his sister against all odds?
It’s hard to tell, really. I should point out we don’t actually know what happened to Caliborn’s Dream Self- Like… Okay, listen.
Since ‘predominating’ is Assimilating the Cherub’s Counterpart, it feels like it wouldn’t even make a Ghost to ‘kill’ Calliope or Caliborn that way, making the Callie Ghost in the Bubbles the one coming from Jack stabbing her on Prospit. Derse is far away enough that in a Dead Session, it wouldn’t get sucked into the Black Hole. Given Alt Callie said she kind of wore him down little by little, it means she predominated the normal way and not by cheap tricks killing Caliborn. For all we know, she reduced him to nothing- Likely leaving his Dream Self comatose and unmoving rather than Dead in Derse, and as such, not producing a Caliborn Ghost.