I believe that the rules of NLI lock someone in for a set period of time which is different than being on campus and then hitting the portal. It used to be a year, I don't know what it is now because the rules change all the time.
To your point though, if you request release I am fairly certain that the CCA grants it if the head coach left. I had forgotten about that provision, but it happened with kid from the school I coach at a few years ago and at least at that time it was a black-and-white process. All you do is file a request for release and then they approve it.