I'll take a stab...
1- Some, but not as many as suspected. The timing (and continued uncertainty) will make that less of an impact, IMO. Now, recruiting? Those conferences/teams will take it on the chin.
2- No. I think they will pretend that they are having a spring season, knowing full well, they won't be. In the meantime, they will be putting backstage pressure on the ACC, BIG 12, and SEC higher ups to join them on their lonely island.
3- I tend to think no, but good (rich) attorneys will tell you that contracts are made to be broken. And I don't think Nebraska would be saying what they are saying if they were not open to jumping. Could this be a fracture that leads to a break in the future though? I believe so.
4- I'm not sure they do much of anything until they see how their own season goes. If the SEC, ACC, and Big 10 pull this off though, they aren't going to bend over backwards for the rest of them. It's way more complicated for the NFL to make sudden changes because they have their own special set of barriers (the owners, the NFLPA, and their own contractual obligations).