Not sure I'd consider it a long shot if they go with this format. What other indoor options are there in the B1G footprint? The 7 listed above already includes Milwaukee, where I don't believe a football game has ever been played. The only other option that exists even close to the B1G footprint that might be superior to UNI-Dome is Fargodome.
I still like the idea of that 9th game being on campuses. Reducing travel has been at the crux of fighting this pandemic, so why have 6 teams travel that don't have to? Also, avoiding cold weather games is more about fan safety than player safety, and that factor would not exist. There are rarely days in mid-December that are dangerously cold, anyway. They could always have some indoor stadiums reserved as a back-up if outdoor games are anticipated to be a problem as the day approaches.