The rep for oboe at Curtis is pretty much prescribed.
My daughter is young but has friends at several schools you mention, but I don’t know what their audition materials were.
The kinds of questions you’re asking make me think you might want an audition prep specialist. The name I’ve heard is Anne Marie Gabriele of Los Angeles.
My daughter has heard that the Oberlin prof doesn’t give sample lessons.
At BU, Robert Sheena is very personable. My understanding is that John Ferrillo doesn’t typically work with undergrads there (but he does at NEC).