spoilers:
I gathered that thing about Gigantomachia isn't just that he can possess multiple quirks. It's that he can do it without it messing up his brain, like with the Nomus.

I wonder how Ujiko got the goop warp quirk since All For One had it during the fight and I don't think that they could've met so that Ujiko could recieve it.

From what we can see of the good doctor I am more and more leaning towards the theory that this is the same dude as the doctor that declared Izuku quirkless. They have certain similarities.

It'll be interesting to hear Shigaraki's answer. Because he's seemed a bit aimless recently.
end of spoilers