This is about as official as it will get for a few of the assistant coaches:
http://www.freep.com/story/sports/college/university-michigan/2015/01/05/michigan-football-coaches-dj-durkin/21298041/
"Michigan has yet to announce any additions to Jim Harbaugh's first football coaching staff, but there have been reports and rumors -- and it appears that several now can be confirmed.
Tim Drevno, D.J. Durkin and John Morton appear in the university directory today."