There are only 123 now, I think (about a 120) division 1A (BCS/FBS/Power 5, Powerlite6 - whatever you want to call it) head coaching jobs in the entire country. In each year, it's a small percentage of those, that are actually available.
What it means, is that there are a lot of people, for a very few spots. The NFL, coaching is a weird thing, once you are in the mix in the NFL as head coach,you tend to circulate and stay in the NFL quite a bit, even if you lose a lot. It's usually up to the person to lose so terribly that they aren't hired anywhere, and or they choose to get out, and then it's just as hard to get back in, as it was originally.
But it's different in college, there are jobs for college coaches everywhere, and of course, the pay scales reflect it. It's much more about performance in the collegiate ranks - getting yourself up the ladders in the jobs and pay scales, than it is who you know, which is the NFL.
THat said - in any business, your reputation and how you do business is all you got - especially college football. Manuel was clear yesterday, and I agree with him, that he's going to do what he can, and support the existing coaches at the same time, using his contacts, but he's not contacting anyone, in any fashion, that he wouldn't want done to him, for his coaching staff.
Hiring consulting firms, that contact agents, and go through intermdiary steps, and in many cases will initiate contact with people without the permission, consent or knowledge in any way from the people that are actually eventually going to be hiring, just so that these kinds of boundaries, explicitly aren't crossed.
That's my take on the whole thing. ANd with that - I do think that this head coaching job, is essentially TJ Weist's to keep or lose. Much like what Manuel did with Ollie.