The pursuit of candidates at this time is very smart. This is the last time the Bills will have leverage due to them having the only open GM/Coach position at this time.
This was probably Russ's idea and he sold it to Ralph. Once the season is over and multiple teams fire their coaches, the Bills will lose that leverage.
On the other side, the potential candidates could wait until the end of the season to see what is available, which is probably what most will do.
What we have here is a sense of urgency on the Bills behalf, knowing they can court all the highly qualified candidates and the knowledge by the candidates that the Bills want to get a deal done relatively quickly, giving them some leverage. For those interested, like Shanahan, this could mean a good deal and a chance for them to get a jump start on evaluating the team, assessing needs and building a short list for the the new staff.
Both sides are ripe for a deal and I predict the Bills close this search out before the end of the season.