Ok is there any chance Luffy and Robin aren’t just half siblings but full siblings? Like was Robin’s mom luffy’s mom but the kids were split up?
It could be possible for sure, though I think Luffy's disposition is so far from the geniuses of Ohara that it's less likely. I do think it's interesting that Robin's mom had white hair (she was the same age as Dragon, so it's not from being old) and Luffy's awakened form gets the white hair. I think it's more of a super saiyan thing, but Oda loves easter eggs that become obvious after the fact.
Like how he had Saul get "killed" by an attack literally called Time Capsule that we'd seen other characters survive. And there's a new theory that everyone seems to be hopping on which is...Jaguar D Saul is the burned man/man marked by flames that Law and Killer are looking. He was all bandaged up and may have freezer burn rather than fire burns (or the fire of Ohara marked him even though the ice kept him alive). Considering that he knows where the library of Ohara's books wound up, he makes a lot of sense.
That also sets us up to get Killer and Kidd meeting Luffy again at Elbaf. It's conveniently the location where people expect Shanks and Luffy to meet again, and Shanks has history with Kidd as well. This would also fit into my theory that Luffy's pirate alliance from Wano will all fight/compete against each other before the end of the story. It only makes sense with the chase for the One Piece, but I think it gets downplayed a bit (especially for Law who literally acknowledged them being rivals with his departing lines although Chopper and Luffy laughed it off).
Edit: One more theory I'm seeing that I didn't know about is that the Kuma Pacafista are actually planned to betray the government. Vegapunk and Kuma were both friendly with Dragon and the Revolutionaries. Vegapunk might be one of the highest ranking Sword members in this case (I'm rooting for Garp to secretly be involved and working with Dragon too but I haven't seen much to support this beside them being father and son).