I think Andy Warhol's mom was an Si type because she fed him Campbell's soup every day for lunch, she seems like a very routined, systematic type. Can't really go beyond the fact that I believe she was an Si type.
Valerie Solanis is an IxFx with Ni...either INFJ or ISFP. I know that's pretty vague, but I can't really say other than she seems like a feeler who was highly concerned with her ethics to the point of obsession, and that she was a writer (again you see this a lot in ISFPs, INFPs, and INFJs...being writers...) and I think she was an Ni type because I believe she saw her assassination of Andy Warhol as this big "symbolic" thing, rather than some practical killing.
A crazed INFJ with a spike of inferior Se violence? An ISFP prone to impulsive action but with a "symbolic" Ni flair for her feminist Fi cause?