It would be extremely entertaining to have Sam Winchester, Sam Oliver and Adam Young together in a room. It would be epic! The Sams could trade stories over whose life sucks more, while the only actual Antichrist in the room looks on in amusement. And ya know, takes care of that Apocalypse thing for Sam and Dean. Or at least gives Dean some powers to even things out (yep, I'm never gonna shut up about this).
Oh yeah, Dean's there too, to spice things up. And who knows, he could be an antichrist as well, according to the SPN comic he was conceived in a forest with a hellhound looking on. If it were a horror film or some such, that would be a big red flag.
And I bet Crowley and Aziraphale show up later as well. Crowley purifies Sam's blood and stops his whining, then goes out drinking with Dean. They swap car stories. Aziraphale has tea with the Sams and Adam.
Ooo. And we could throw Jake Gray into the mix too!
Oh, the epic LULZ that would result. Sam Winchester, Dean Winchester, Sam Oliver, Adam Young, Jake Gray, Aziraphale and Crowley, all together. HEE!