Is it ok to wear a top that is the school’s color when going to a college interview?
Why not – unless it is a very strange or unflattering color - go for it if you want to!
Wear any color but that of their rival school!
Ya, I wouldn’t show up to USC in that bright blue color. 
Yes, but I wouldn’t recommend wearing any actual school gear- that’s going a little too overboard
Purple is always appropriate…
Don’t be gimmicky. If it’s naturally a color in your wardrobe fine. Clothes (and their hues) are meant to seamlessly present the person – not for you to be a walking billboard.
If a female interviewee wore a blue/white (my school colors) outfit, I wouldn’t even think to equate that to my school.