coaching pool being so small is that the administration can be very educated about each of the candidates and keep a pulse on their interest so that if and when a change comes there isn't a lot of time needed for information gathering and making a decision.
So while I'm sure there was some conversations to be had with Burgess, Madsen, etc. if BYU knew Young was their top target and Young showed interest in the position, there would be no reason to drag out the process. That doesn't mean they didn't do their due diligence beforehand. It just means that due diligence led to a single candidate that they ended up hiring.