So anyway my DFO evidence:
MANGA SPOILERS
It’s strange how Izuku was (supposedly) the only OFA holder who inherited the quirks of the vestiges, huh.
Now, Izuku COULD have gotten the quirks for plot convenience, but m e h.
I think that the reason he got the quirks was because of an improved AFO:
Telekenesis + All For One: Stealing Quirks from a certain radius. (Inspiration for this idea came from a fic I read on AO3, isn’t that nice?)
NOW, why didn’t Izuku steal the others’ quirks? It’s most likely that, either Izuku’s morals were preventing him from meeting the conditions to steal quirks, or simply that his AFO quirk is dormant, and hasn’t activated-until now.
The reason it affected the vestiges was because they were in his mind (or the OFAscape, I don’t think there’s a name for it), making the quirks much easier to steal.
If the quirks are linked to the souls of the OFA users, then it would probably be much easier to steal the quirks, considering you wouldn’t need to rip through flesh and bone to steal it.
As for why he can’t use it to his full extent after awakening it-well, it could most likely be that OFA itself is restraining him from using it, due to it being not only the rival quirk, but also due to the fact that Izuku would practically be a god by then.
AFO could also be the reason Izuku isn’t a Noumu by now, having at least four quirks (counting AFO)-and the reason he can use them.
So yea Dad For One is canon in my eyes and I’m trying to make them canon in yours