HA! More expansion talk!
1) When Missouri begged for entrance, B1G was looking for 1 team only, and when the slam dunk Huskers came along Mizzo got regulated to bridesmaid. Missouri showed their hand, felt they needed to make a move, and felt very fortunate to land in the SEC (thinking the B12 was gonna implode.)
I think Missouri will make the decision that is best for them, I don't think they would actively campaign to leave the SEC like they did the B12. But if an offer is there from the B1G it would merit strong strong conversation.
Athletically, B1G is tops again in revenue (B1G 41-50 million depending on source, SEC is 34-40 million depending on source, so even best estimates for SEC and worse for B1G; the B1G still has a slight advantage.) and Nebraska and Illinois offer better rivals than anything they are getting in the SEC now.
Academically, B1G is head and shoulders above any other conference in Graduate Research, Missouri as an AAU member have shown graduate research is very important to them.
Logistically, Missouri would be the easiest to move. No long standing rivals, and no loss of media rights.
2) Now for Notre Dame, IF and only IF an 11-1 ND gets passed over for a 12-1 conference champ would the Domers discuss increasing conference participation (not join just increase.) I would guess ND would compromise a 6th game to the ACC with the huge caveat that if they have the same or less losses and a higher CFP ranking than one of the other participants in the ACC title game they would replace that lower ranked team. ACC title game suddenly just got a lot more interesting. ND would have the chance to have a marquee win at the end of the season, ACC would reduce the chance of having a lame duck champion, there would be a lot of hype.
3) Virginia Tech and Nebraska find themselves in a similar boat. AAU with the stroke of a pen declared Agriculture research to not be "competitive research" and didn't count towards AAU status. In the same year they also declared that research held "off site" would not count. UNL was including the medical research held at UN of Omaha as part of their total research portfolio. In one year, the 2 biggest forms of Academic research Nebraska did was not longer counted towards AAU membership, they lost membership and declared they are not interested in being part of the "prestigious group" any more. Along comes Va Tech, they applied to AAU and requested to have their medical research facility in Roanoke included. If it's incuded I think Nebraska has a legitimate complaint, if it's not included Virginia Tech is probably not granted acceptance. I think Big Ten Big Wigs are watching this closely on 2 fronts, they would love to have Nebraska back in the fold, and if Tech gets accepted they become a much more palatable candidate for expansion. I also believe that Va Tech, is the lowest hanging fruit in the ACC, and alot easier to get than say Delany's alma mater North Carolina would be.