How's Valor able to carry Quinn anyway?

Its likely that Valor is simply extremely strong for a falcon. Just like most human fighters are extremely strong for a human.

Valor could grip her by the Talon

Your question kinda comes under a recent discussion, which I found the following to be the best response to that as well as this.

{quoted}

I feel as though you dove too deep into a simple idea. We all know that the game is not cannon, which means that it is possible for certain abilities to be exaggerated.

Ex: Darius probably doesn't jump 20 feet in the air, this could be a "buff" to make him (in-game) more of a legend.

I'm just not aware of any lore specific answer.

Valor is big. That's how.

Cause fuck logic that's why

We have a fish that buy boot to "run" faster , a bird carrying a women is not the biggest concern here.