Because of the Big Ten Network, there would be lots of financial incentive for current teams to leave their conferences. The BTN would surely be able to produce more money for hockey coverage than is currently available. I have no idea what FSN pays for college hockey but I bet it's pretty close to zero.
So, if ND ends up in the BT, you currently have OSU, MSU, UM, WIS, Minn and ND playing varsity hockey. That's six teams and I believe that is enough to form a college hockey conference.
Moreover, several BT teams play in the American Collegiate Hockey Association which is the governing body for club hockey teams. From what I understand the quality of play is quite high and the reason these teams are not varsity is Title IX considerations. I believe that the BTN money would provide enough funding to not only create men's varsity hockey teams but also women's teams.
So even though there would be enough BT schools to form a six team conference, I believe that there would be additional teams elevated to varsity status and there would be a Big Ten women's hockey conference as well.
Schools fielding club teams at the D1 level include: Indiana, Illinois, Penn St. Additionally, Northwestern and Iowa field club teams at the D2 level. So the infrastructure is there for varsity programs.
Also, potential member schools Pitt, Rutgers and Syracuse all field club teams.
I don't think it would be an issue to get the current BT schools to leave their current conferences; especially given that they would be making huge amounts of money compared to what they get now.
Hockey is the least of the many considerations for expansion. But, it is one more thing that would be a side effect of the expansion. It would produce more television inventory including a conference tournament and potentially the GLI and NCAA early rounds.
I am highly confident that there will be a BT hockey conference in the near future.