Eh, TCU is certainly different from BYU in terms of trepidation about the school's policies, so I don't think that's a sure thing. And Texas Tech and TCU are in the same "market" just like Kansas and Iowa State are. That is to say, not at all.
If expansion does happen with the Big 12 falling apart, I don't think every conference will be scrambling to get to 16. The B1G may stand pat at 14, or maybe they do jump to 16 while the SEC stays where there are. The B1G prints money as it is - I very much doubt that Kansas or Iowa State (2/3rds of the AAU schools in the Big 12) are on their mind at all.
you need to visit the campuses of Cal and Stanford.
If given a choice of voting for TCU or North Dakota State, they would take NDS.
If given a choice of DMAC or TCU they would take DMAC
No private school with religious ties will ever sniff the PAC 12