4. Ryan Nielsen, DC, Falcons
I think Sean Payton would have loved to have hired Ryan Nielsen this past cycle, but he had his sights initially set on Vic Fangio, and when Fangio turned him down, Nielsen had already taken a job with Arthur Smith's Falcons.
In short order, those Falcons may no longer be "Arthur Smith's" Falcons. If the Falcons make wholesale changes to their coaching staff and Nielsen becomes a free agent again, perhaps Payton would go to someone he's familiar with.
Nielsen was an assistant on Payton's staff in New Orleans starting in 2017, and has steadily risen up the ranks ever since.
5. Brandon Staley, former HC, Chargers
The much maligned and fired former Chargers head coach might not be the most popular choice, but Staley did once coach the #1 overall defense in the NFL when he was with the Los Angeles Rams, a major reason why he got the Chargers job in the first place.
Staley is a disciple of Vic Fangio, which seems to be a defense Sean Payton wants to run, and Staley is not far removed from his own stint in Denver as one of Fangio's assistants. Since Staley won't be in charge of making decisions on the game management side of things and would only be in charge of calling the defense, I think this could be a solid option, not just for the Broncos but for Staley also to rehab his image overall.