I feel like you are over-valuing some of these smaller schools.
SDSU is considered a joke of an academic institution by the locals.
Boise State is not going to move the needle in any way, especially academically. But small population. All 50k fans go to every game, so no TV viewers.
Intel is barely alive in NM with many feeling that Intel will close it down soon. It is a manufacturing facility. It's a minor part of the landscape.
UNM fits for other reasons, but don't believe their population growth is enough to move the needle.
Las Vegas has some population, but much of it is retired folks from elsewhere or younger people who are unlikely to stick. Most having no affiliation with UNLV. Getting traction in that community will be near impossible.
And that's the problem. There are no perfect fits within the existing footprint (though I'd point out that SDSU is a Tier 1 research institution).
You don't want to lose your DNA as a conference. That is a conference killer.
For conference DNA, I'd say the following:
1. Western US, so nothing east of St. Louis.
2. University in a growing, dynamic community.
3. University is research-based, especially in high-value technologies (aerospace, computer science, medical, etc.).
4. Not just a football school - strength in Olympic Sports.
From that starting point, you start looking at expansion targets based on what it could mean for media revenue gains, exposure, and recruiting geography.
Within that, it's a relatively short list and I don't know that any school checks all the boxes. Here are the two obvious ones:
1. University of Texas at Austin -- AAU Member, Tier 1 research, Austin, TX media, TX recruiting, national prestige, . Maybe the most valuable program in the nation, no matter what we might think/know about them. Would certainly change the culture of the Pac-12 to as much southwest in flavor as it is pacific currently. 46 NCAA national championships with 9 more that weren't from NCAA (4 in football, 5 in Olympic).
2. University of Oklahoma -- Tier 1 research, Oklahoma City with significant reach into Dallas, national prestige. 25 National Championships plus another 7 MNCs in football.
From there, I think a case could be made to add 2 more from a host of schools that wouldn't necessarily move the needle on revenue but would check enough boxes to make sense. Kansas, Missouri, Texas Tech, Houston, New Mexico, SDSU, Boise State.
The big question, I think, is what the hell does the Pac-12 do if it doesn't land Oklahoma and/or Texas and expansion is necessary within a new D1 landscape? There is simply no path to competitive revenue if we see a B1G, ACC and SEC each with 16 teams. B1G snagging KU and OU with the SEC or ACC snagging UT would be a nightmare scenario for the Pac-12.