I'm less optimistic than others here about the caliber of coach Michigan could pull away from their existing gig. I could see Warde keeping Donlon on contract while negotiating with candidates and allowing him to interview for the job.
I also agree to not make the change in mid season because this team could shoot itself to an upset win on any night. That win wouldn't be a fair reflection on Donlon's abilities in the lead chair.
There isn't a Harbaugh candidate out there. I don't believe that there is a Hoke candidate out there. If you are going outside the program for your next coach, you need someone who views this job as a destination job. I'm sure others disagree.