Of course, off the top of my head, Ceglarski, Lucia, and Gaudet switched to their alma maters. The latter two still coached as of last night. I don't know about the others.
For the record on the others
Comley was a LSSU guy where he began coaching, Mancini played at CC, Higgins was played at BU around 1960, Sneddon was a Harvard man. Mason played juniors instead.