I don't have anything new about the Big 12 and Pac 12 except ongoing discussions on some type of cooperative collaboration. It could fall apart, it could shock the world.... anything is possible until its not.
Let me add this for BYU fans looking for something... this is just my opinion, but its an informed opinion. BYU, right now, would be the next program in the Big 12 should WVU leave for the ACC in 2025 and BU isn't dropped.