Notre Dame is not joining any conference in Football. Not the Big Ten, not the ACC. There is no reason for them to ever do so. The reason went out the door when the CFP said that you don't have to win a conference to be eligible. They are not going to change that. Plus, the CFP will expand to 8 teams within the next 10 years. At that point, there will be a 0.00001% chance that Notre Dame will join a conference.
Pitt is bound by the GOR. Big Ten is not going to invite any school bound by a GOR because it weakens their own GOR. The only conference that will try to invite any schools bound by a GOR would be the SEC because they don't have one. Why would anyone who has a GOR try to weaken their own GOR? That is stupid.
I know it is fun to make up realignment scenarios, but they have to be based in reality, not fiction. This is more fiction that Iowa State ever going to the Big Ten and I think Iowa State going to the Big Ten has about a 1% chance.