Is a chull able to receive some form of Investiture? ...I'm thinking of Scadrial... Would it have the presence of mind to be able to use the abilities?
Not as it is right now. But you can see in the way that Ryshadium are working that we have animals that are reaching beyond-animal intelligence. Aviar are the same way. And it is possible to assume that you could get to the point where you could use such powers. But none of them are there yet. But the Aviar kind of use their powers, so I guess some of them are. So, yes, I will say that's possible.