Seems like they struggled to find 10. I expect Hairsin and Heupel to fail spectacularly. I'd gibe Hairsin a 25% chance of success and Heupel not more than 10%.
Harsin's chances of success are most likely tied to the larger question of "how much longer is Saban at Alabama?"
I don't have the reflexive "I hate everything Auburn" that a lot of folks here do; of course, I also don't live in the state of Alabama, either, so maybe that's part of it, too. But looking over the history of their post-Shug hires:
Doug Barfield (29-25-1) - inherited team hit with sanctions in the second Bryant run; peaked year four, fired after five years.
Pat Dye (99-39-4) - inherited probably a better team than assumed; peaked in year three when his team should have won the national championship; downward slope for three years, followed by building the most solid SEC program of the late 1980s. Dye's ascent coincided with Alabama hiring Bill Curry and LSU hiring Mike Archer; his descent coincided with Florida hiring Steve Spurrier and Alabama hiring Gene Stallings.
Terry Bowden (47-17-1) - inherited a team on probation and won his first 20 games; of course, this means after he stopped winning, his record was 27-17-1, and Bowden's team peaked his first year. His SEC title berth coincided with Alabama hiring Mike Dubious and Florida having a rebuilding year (by their high 90s standards).
Tommy Tuberville (85-40) - inherited a train wreck. Growing pains for five years - to the point of Jetgate. Peaked in year six with an unbeaten team that would make a modern playoff. Went downhill pretty quickly and got fired/resigned/whatever the moment he lost to Alabama with Saban ascending.
Gene Chizik (33-19) - got Cam Newton, peaked with a national title his second year, fired after not being able to replace Cam.
Gus Malzahn (68-35) - peaked first year and came within 12 seconds of national championship; never really came all that close again, though a second ascent in 2017 that gave him leverage enough to get a generous buyout that netted a 15-10 record after he got it.
Barfield - peak in year 4
Dye - peak in year 3
Bowden - peak in year 1
Tuberville - peak in year 6
Chizik - peak in year 2
Malzahn - peak in year 1
You can throw out Barfield for at least three reasons:
1) he took over just as scholarship limitations were coming in, so the situation was different
2) he took over a team serving a severe probation
3) he took over just as Bryant was blooming the peak of his second huge dynasty
The rest of the guys came in and basically did a good job with the material they inherited. Dye walked into being able to walk into living rooms and say, "Coach Bryant isn't going to be there because retirement age" yadda yadda in 1981, and he also benefited from some incredible arrogance on Alabama's part in recruiting, which is part of how he got Bo Jackson.
It is my own personal assessment that Pat Dye is really the only coach in that group that I'd call a VERY GOOD head coach. Most of the rest weren't even big names when they hired (though Tuberville was considered a bright prospect because he was winning at a very crippled Ole Miss). One can argue that Tubs only lasted as long as he did because Bobby Petrino didn't take the job. Remember - even for all the "ya gotta win the Iron Bowl" nonsense (which is still more of an Auburn than an Alabama thing), Tubs had won three of four, and they were still trying to replace him. Then he went undefeated and like Fulmer, it became nearly impossible to fire him.
The point is, there's a general pattern with the Auburn coaches:
a) early success and peak
b) decline of various speeds
c) maintain the job by continuing to be better than Alabama
The real outlier is Dye, and he was a very good coach. And even then, he DOES follow the pattern, he just lasted a lot longer because he was a good coach. Circumstances have more of a halo effect on you as a coach if you're just a mediocre to average coach than if you're a very good one - because the talent of the good one overcomes circumstances (CNS is a perfect example).
It is possible, of course, Harsin could be another Dye. The part that makes me wary is that Boise State has had many more duds than studs who look so good on that blue turf and then go to real conferences and get sliced and diced.