Ok lets see if I got this straight... On the ship JOhn's denizen knew about original John's time adventures so it killed retcon John (and davesprite) so there wouldnt be two Johns, leaving Jade alone for three years where she goes to sleep and meets an alternate Callie who tells her stuff. Much later Jane kills Roxy before Vriska puts her to sleep. Original Roxy and John will now enter the retcon universe with LOWAS

Yeah, pretty much.