Michigan might not have been able to hide behind FERPA with the Fab Five case, but I'll bet that we could have just fired Steve Fisher and blamed the entire thing on him while claiming that there's no way he could have known what was happening in his program. In that case, we could have just hired Dutcher as our head coach instead of Ellerbe and gotten a lot lighter punishment.
First of all, the most damning information in the Michigan basketball case did not involve any sort of university communications at all. (No email or text messages to speak of at that time, etc.)
Secondly, what was damning was the apparent records of payments by Martin to Webber and others. Disclosed by the federal criminal investigation of Martin and Webber.
Michigan was linked only insofar as Martin was (sadly) determined to be a "booster." Essentially making Michigan vicariously liable for the independent depredations of Ed Martin. The NCAA (not ESPN) pored through comped ticket lists, travel vouchers, and related things to see how close Martin was to the program.
What you are talking about -- some sort of proactive, prophylactic early firing of Steve Fisher (who got fired eventually) has nothing to do with FERPA; it would merely be a strategy for dealing with the NCAA, which already got everything it wanted without any FERPA claim at all. I don't understand what you are saying about OSU by way of comparison with Michigan. FERPA didn't make any difference to Michigan's basketball sanctions.
Nowadays, with email and texts and Twitter and Facebook and all other manner of social media, some of which is run through "umich.edu" accounts or on university-issued phones, something like this could easily snare Michigan, and we could see an NCAA investigation come and go (let's say it was nothing in the view of the NCAA) but still have ESPN pestering Michigan to release a bunch of documents and records via a FOIA request. In that case, we will become comparable to OSU's legal position.