>>101368961It's not clear but it looks like they will definitely coexist and Slott and Zdarsky already had plans in place for the return. Now the way I see it (and judging by these solicits), Ben and Johnny will be stranded in another universe and eventually Ben will be desperate and tell him the truth, that Sue and Reed are dead and that he was just carrying the hope to see them again despite knowing it wasn't possible. All of this due to Rachna ditching them with the Multisect.
Meanwhile, the First Family come back to 616 and try to make sense of all the things that happened (addendum: I REALLY hope they address the stuff that went down in Ultimates and that Galactus does go back to his Ligebringer role or at least it's addressed), and then Reed tracks down the Multisect, assuming that Ben found it only to find Rachna, who's not only running from Ben and Johnny but from the Thinker, after he finds her lab. Reed then uses the Multisect to track Ben and Johnny back and the long awaited reunion takes place.
I swear I'm not Zdarsky.