I would highly doubt that ND gets added as a hockey-only affiliate to the Big Ten.
The BTHC is likely to materialize within the next 5 years after Penn State's program is fully operational and has a bit of experience under its belt, but the Big Ten's presidents were hesitant in the past to add hockey-only affiliates and could never agree on whether to create a BTHC with the 5 other hockey members and ND or a mix of Miami (Ohio) and others...
They decided to push off the decision based on tradition, since unlike the Pac-10, which has affiliate members for sports such as the Olympic sports, the Big Ten presidents have never been able to reach agreement on allowing affiliate members; several of the members are extremely hesitant due to tradition-based reasons.
Now that Penn State will be a potential 6th member, enough for a BTHC, I'd expect the presidents to simply bypass that contentious issue and create a 6 member BTHC that allows enough non-conference games to allow the CCHA and WCHA to continue to receive visits from the marquee Big Ten teams.
Finally, a BTHC will possibly put pressure on Notre Dame to eventually consider it to be a major plus to joining the Big Ten. Notre Dame is building a brand new, expensive arena that has a much higher capacity, so they will need visits from the Big Ten teams in order to sell their season ticket package. Obviously, a CCHA devoid of Michigan, Michigan State, and Ohio State may play a secondary role in convincing Notre Dame to eventually join the Big Ten, since their hockey program may struggle without it, and hockey is perhaps the 3rd most important program there even though it is a distant 3rd...