Think you have that reversed. It’s most likely Oregon first. Even though their fans aren’t happy about it, it makes sense for them to jump. Washington is a horrible fit but they are probably going to get forced
Washington has always been way more of a geographic island than people realize.
In terms of what isn't a "fit"...maybe some still care about academic profile but the Pac is gonna bring in SMU, Fresno, etc...so might as well go Big 12.
They fit with the Big 12 better than SDSU, Cal, Stanford in that they have a real true fanbase.
In terms of being in a big city as opposed to a small college town, the Big 12 now has Houston, Dallas, Denver, SLC, Orlando, and potentially Phoenix. Boulder/Provo is basically Denver/SLC, we're talking 15 minutes and you can't tell when you leave one and enter the other.
The main reason I don't care to add Washington is I am sick of teams looking to be elsewhere. They aren't far enough away from a definitive Big Ten "NO" for me. Let them hold a weakened Pac together for a few years and if they don't get their invite they can come thrilled to be part of B12.