If JD & Rick promised Frost that they would not transfer to a Big Ten school, in order to get Nebraska's agreement/sign off on a transfer, then that is kind of that. Don't see how you can go back on that and get the waiver, as I believe the former school has some say in it.
Unless it is Iowa St, then JDS does not deserve a waiver to be immediately eligible for the 2020 season, in my opinion. TCU would be ridiculous. It doesn't matter that the coach who originally recruiting him is there now. That's still closer to being an undergraduate free-agent, than not. And that is against the core tenets of the NCAA (so they say).
Coming home, is worthy of a waiver. Doing the opposite of that, is not.