Here's my problem about coaching hires:
What the hell is the big rush to get a new HC before the 2nd week of Jan? The most successful programs will be coaching up thourgh Superbowl Sunday. Why not wait, interview them in the offseason or the week off between the Conference Championship games and the week before traveling to the Superbowl? It seems like the best candidates would be from that group.
I like the DC in ARI, Denver, KC, and Seattle. OCs in ARI, NE, PIT, & DEN. That's who you target. People who have built Superbowl quality programs. Not scrambling neverrans, and pretenders. Sweet! We got Cincinnati's OC! Congrats, but don't pat yourselves on the back too hard, he'll be looking for a new job in 2 years...
The Superbowl is Feb 7th. You have a full week to decide who you want as your HC after the SB. That gives the new HC 2 weeks before they have to help decide on Transition or Franchise players. I would argue that the HC still isn't really needed for that, this job can be done by the GM. I would however, want my coach in place by the start of the combine, which is usually in March.
I just looked up this year's combine, and it's set for Feb 23 to start, so my timetable would have to be moved up this year. Here is how I would approach the interview process: 1/25-1/28 interview any and all coordinators who are participating in the Superbowl. They have priority because they have to travel, plus if you really like one of these guys, you have to wait on the hire. Fit in the rest of your candidates who lost in the divisional or championship rounds 1-27 through 2/3. Now you have a pool of 8-12 highly qualified, productive coordinators, who have shown they can either build a successful program, or have shown consistency over time in keeping their programs competitive.
If one of the candidates, that is not participating in the Superbowl, wows you, then you can hire them immediately (probably by Feb 1). Worst case, you can hire your HC the Monday after Superbowl giving them 2 weeks to hire their staff and prepare for the combine. The scouts should already be in place, but your team philosophy may change due to your OC and DC hires, so it's good to have the types of players you want to target, ready by the start of combine.
I mean, what advantage does any team have hiring a guy 5-6 weeks before combine vs 2 weeks before combine? I'd say my metric would get you a better quality hire, and possibly, more stability in the long run.