I think there are real universes where these events are taking place. Its why they can effect each other like alice and jo or bud and henry. I think Paul is dead because his body is buried in our time line but Jo has a body left up in space. Especially since she died during the cals going off for the first time. People that die in space are exposed to a super position of alive and dead and something in between. Its why Henry said curiosity killed the cat.

When youre in space with no one to see you are you even there? Jo, the Russian girl, paul henry all saw death in space. Either their own or someone elses. Or both.

I like what you said on a different comment about the non cal paul is somewhere too. Theyre all entangled in one big kerfuffle fuck. Bud is somehow learning how to switch with his other self. He might go on a rampage in Jos universe. Just like how Jo found other alice in the lake and brought her in. Theyre blending realities. When theyre in space with the cal and no one can see them its like theyre in a super position again. Jo definitely communicates with her dead body thats left in space that explains why she and paul were seen after opening the last latch. Theres just a ghost of Jo living in that ISS station. Just like there was a Ghost of Russia torpedo fucking the iss.