If UCF is number 5 in any equation, it's not 1 or 2 in a 2 school expansion. I firmly believe that in a 4 school expansion, UCF is solidly in regardless of the other candidates. Don't think I agree with your assessment that UCF is #5 in the 4-team-including-Houston equation.
The Big XII would be absolutely foolish to give Memphis an invite. Memphis is lightyears behind the other top candidates with respect to academics, athletics, enrollment, surrounding population, and media/financial gain. By nearly every metric, they'd be a terrible invite in comparison to BYU, Houston, UCF, and Cincinnati. I don't see UConn, Tulane, or USF as viable candidates at this point. (USF's NCAA investigation did and should have taken them out of consideration immediately - the conference has enough investigatory struggles at this point). But I guess we've seen the Big XII leadership be foolish for years.
It is absolutely true that 0-12 couldn't have come at a worse time. Really any bowl game following the preceding successes would have UCF in much better position. However, Rutgers move to the B1G should teach us that, in the end, wins might count for less than most think anyway. If the Big XII has even a sliver of the foresight that the B1G had, UCF should be in.