Not enough good teams left in the B12 or ACC for their to be a P3, if P2 and everyone else. The few programs who may be of value will move to the P2.
My guess at the few with an outside chance
UNC
UVA
FSU
Clemson
AZ/AZ St
small chance but a chance if things fall right
Va Tech
Kansas
NC State
Duke
Miami, FL
Ga Tech
Utah/BYU
Cant think of any other school who has any drawing power that will matter. Enough states will be covered to keep Congress happy.
For as long as Big Ten presidents have a voice in the academic rigor of their member institutions, the leading candidates for that conference (at least from the ACC) are Miami (FL) and Ga Tech. If/when FSU gets out from under the ACC's GoR, the Hurricanes and Yellow Jackets will be first to land an invite. Clemson and FSU will only have a shot at the Big Ten when academics stop mattering to them.
The Big XII will continue to exist as a "Power" conference due to their basketball strength (though obviously a half-tier down from the P2 in football). Clemson and FSU have a shot at landing there if the SEC doesn't grab them first. (Which will be just fine for South Carolina and Florida.)
If the Big XII continues to exist, Kansas will stay put. If they're forced to move, the Big Ten would grab them up for the same reason they'd take Miami and GT.
I don't believe UNC/Duke/NC State split up for anybody. The jury's out on Wake. They'll either move together to someplace like the Big XII (see basketball strength) or they'll remain in a greatly diminished ACC, which would look far more like the old pre-split Big East than the SEC. High-end basketball matched with 2nd tier football. Honestly, though, I don't think the ACC survives. They'll all go to the Big XII. At least it's only a half-tier down from the power conferences. That's better than being a full-on G5.
The 2PAC will also vanish, once Wash State and Oregon State are done milking the conference of its remaining NCAA tourney credits. The Big XII could provide a home for both.
The ACC teams who aren't good enough or big enough for the Big XII are the ones who'd be screwed in all this. They'll likely fall into whatever the G5 looks like at that point. Probably into the American, but don't count out the SBC or even CUSA.
It's hard to kill off a conference at this level, though, so there's a good chance the ACC and 2PAC might merge, just to try to retain some "Power" status. I don't see it, but I can't rule it out.
If that happened, you'd end up with the Big Ten, SEC, Big XII, ACC2PAC, AAC, MWC, CUSA, SBC, and MAC. Only the Big Ten, SEC, Big XII, and ACC2PAC champs would be guaranteed a Top 4 slot. There'd still only be one slot guaranteed for the highest ranked G5, and that team would not usually end up in the Top 4. (A 12-seed would be the most likely spot most years.)
Taking this year's standings, moving teams to their 2024 conferences (but merging the ACC and 2PAC) you would've gotten something like this:
1 (BYE) - Michigan (Big Ten Champ)
2 (BYE) - Texas (SEC Champ)
3 (BYE) - FSU (ACC2PAC Champ)
4 (BYE) - Arizona (Big XII Champ)
5 - Washington (Big Ten) vs 12 - Liberty (CUSA Champ / Highest Ranked G5)
6 - Alabama (SEC) vs 11 - Penn State (Big Ten)
7 - UGA (SEC) vs 10 - Missouri (SEC)
8 - Ohio State (Big Ten) vs 9 - Oregon (Big Ten)
I think they'd put some kind of provision in place to avoid intraconference matchups in the opening rounds, so swap Missouri and Oregon:
1 (BYE) - Michigan (Big Ten Champ)
2 (BYE) - Texas (SEC Champ)
3 (BYE) - FSU (ACC2PAC Champ)
4 (BYE) - Arizona (Big XII Champ)
5 - Washington (Big Ten) vs 12 - Liberty (CUSA Champ / Highest Ranked G5)
6 - Alabama (SEC) vs 11 - Penn State (Big Ten)
7 - UGA (SEC) vs 9 - Oregon (Big Ten)
8 - Ohio State (Big Ten) vs 10 - Missouri (SEC)
The second week of the playoff would match the four seeded teams against the winners of Round 1 (winners based on my projections and 2023 bowl performance):
1 - Michigan (Big Ten Champ) vs 10 - Missouri (SEC)
2 - Texas (SEC Champ) vs 7 - UGA (SEC)
3 - FSU (ACC2PAC Champ) vs 6 - Alabama (SEC)
4 - Arizona (Big XII Champ) vs 5 - Washington (Big Ten)
The CFP Semifinals would be next:
1 - Michigan (Big Ten Champ) vs 5 - Washington (Big Ten)
7 - UGA (SEC) vs 6 - Alabama (SEC)
Followed by the CFP Championship Game:
1 - Michigan (Big Ten Champ) vs 7 - UGA (SEC)
And the winner of the first CFP Championship would be UGA of the SEC.
This result would have officials and journalists raving about how this proves how perfect the CFP is -- how else could an unheralded 7-seed Cinderella like (checks notes) the Georgia Bulldogs ... win the national championship?? THE SYSTEM WORKS!!
Screwed over in this simulation: Oregon (matched against UGA in Round One... that bites) and Ole Miss (the 12th ranked team, left out of the playoff to accommodate the G5 representative).
FYI, I don't see any possibility EVER of the CFP giving a guaranteed Top 4 seed to a G5 champ, or giving automatic berths to multiple G5 champs. The best we could ever hope for would be for the ACC2PAC to dissolve and leave one Top 4 seed available for the fourth highest ranked team, regardless of conference. If a G5 team manages to scratch and claw its way into a Top 4 ranking, then they can get in. Generally, though, we'll just see the one unseeded slot available, usually the No. 12 slot. And as with Liberty this year, most seasons will see that 5-12 1st round matchup end in a 55-10 blowout. It'll be ugly every single year, because the #5 team in the country is head and shoulders beyond anyone in the G5 every single year.