Could that Texas game be CBS?
no
longhorn network?
Likely. We would show it on our TV network as well (last year it was FSN with Ben/Stanbot)
Is this an agreement of our TV deals? If something falls to Tier 3, we all get a piece of it? Or does the home team retain all of the rights?
Do we have to get a special waiver or agreement to broadcast a game on Tier 3 if we're the visiting team?
Tier 3 rights are not exclusive windows. We have the right to distribute the game as the visitor however we would like to do so, whether it be a set up like FSN or on the web, it's up to us.
This happens literally every year, at least 1 or 2 conference games end up on Boylevision. Used to be Nebraska or Clones a lot, it isn't unusual. When we have home Boylevision you might notice a second TV crew at the Bram, that would be the visiting team's Tier 3 crew doing the game.
Most schools like having a couple games fall to Tier 3, home or away, because they can turn that into better Tier 3 rights money. Win-win.