Adding new schools to the Big 12 and making a go of it should be the last option for ISU, the money is just not there from the networks to really make it worth our while unless everything else falls through.
If I am Jamie here is what I am doing, I know now the OU and UT are gone, if this falls through no way in hell they are going to be giving their media rights over to the conference in the future. So we might as hell plan on them leaving.
1st get with KU and see if going to the Big 10 is an option, if so this is the best route for both schools. I have thought for a long time that ISU would thrive in the Big 10 with the added money the conference provides, plus ease of travel to many of the conference schools. This is OPTION 1, 2 and 3 if available.
4. Go to the Pac 12 along with TT, OSU, KSU and try to get the conference to split the leagues into a east and west division. Good road trips but further out, renew a rivalry with Colorado while keeping the ones with the former Big 12 teams. Good but not great money, and it would take time getting used to 9:00 PM starting times but doable.
5. Refigure the Big 12 by adding all the want a b's P5 schools Houston, the Florida schools, Cincinnati, Memphis and the rest into a conference and hope that some network or streaming service is willing to pay 20 million per team for the programming. This option basically guts the atheletic department starving it of resources for years to come, but better than joining the MAC or MW.