Are you going to allow trading in your league? The more established college leagues (Bryson's NCAA, NCAA-FCS and NCAA 2.0) do not.
NCAA 2.0 allows one player for one player "transfers," but they rarely happen.
I would advocate for "not," because there is no trading in real-life college football and because you avoid the bad scenario of predatory trading by experienced coaches fleecing less experienced coaches. Just my two cents.
Good luck with your league project.