Theory 1: He's dead. RIP.
Theory 2: He's off on some important mission
Theory 3: Scopper is the one guarding Laugh Tale, and returned to the island after Roger died.
I forgot to mention this when responding to Shishios post too but I'm thinking Scopper might be that man marked by flames/with the burn mark or whatever. That would be kinda hype especially if Kidd is gonna meet him and get "his own Rayleigh" too? Literally the next best thing after Rayleigh?
My other crack theory was that its Saul, Aokiji didnt kill him as it was said Aokiji freezing people doesnt kill them when he froze Robin and she didnt die ofc, almost like its a deliberate parallel to when he froze Saul too and was trying to kill her too back then lol.
Aokiji did use Ice Time Capsule which is a weird choice of name for a move to try to kill someone with especially, unless he was trying to preserve that person for later and pretend he killed him?
Aokijis ice might be so strong that it can withstand the cannon fire, explosions, wildfire and whatever else was happening on the island and it can float on the sea like an iceberg too. Saul kinda looks like a caveman too, so its even more fitting, that frozen caveman being discovered preserved in ice by modern day people lol.
Time Capsules are meant to be opened MUCH later after they are buried too. Kinda convenient that Akainu didnt actually go onto the island and start going on a one man volcanic rampage and making Ohara his personal Pompeii directly too? His magma would have definitely melted Aokijis ice that froze Saul surely and thus killed him for certain ofc, thus sabotaging Aokijis potential plans for him.
If Saul is alive and thus survived Ohara, then he could be burned by the flames on Ohara if they melted the ice and thus thawed him out before he escaped or he got frostburn from the ice instead?