Defensive S&P rankings currently:
https://www.footballoutsiders.com/stats/ncaadef
Looking at that, first non P5 team is northern Illinois, followed by San Diego state, then Temple, and Fresno State. I'd take a look at those teams, but that's just at a glance
Nothing wrong with your idea, so let's take a look:
NIU - Jeff Knowles -
https://niuhuskies.com/coaches.aspx?rc=900&path=football - From ILL, played at small college there. Although it says he spent his first year at Mankato State, must've redshirted and then left after first year. Interesting history, says he didn't do any coaching from 2000 - 2008. Then coached at his alma mater 2008-13, then was a quality control coach at NC St, then has been at NIU for two years, DC this year. Other than the one year at Mankato, no ties to Minnesota area/programs.
SDSU - Zach Arnett -
https://goaztecs.com/coaches.aspx?rc=328&path=football - Played for SDSU current HC, at New Mexico, where he is from. Has been at SDSU for several years as a D position coach, DC this year. No ties to Minnesota area/programs.
Temple - Andrew Thacker -
https://owlsports.com/coaches.aspx?rc=1798&path=football - From the south and mostly has coached around there, except now 2 years at Temple, DC this year. No ties to Minnesota area/programs.
Fresno - Bert Watts -
https://gobulldogs.com/coaches.aspx?rc=864&path=football - NJ native, played at Cal for Tedford. Coached all over, was DC at UC Davis (FCS/I-AA) for 2013-2016, came to Fresno with Tedford last year as LB coach, DC this year. No ties to Minnesota area/programs.
Interesting that all of these guys, it's their first year as DC at these programs. Obviously having success.
And of course, none of these guys are from the Schiano tree ... though Watts is from NJ and so might have been recruited as a player by Schiano.
Would doubt Fleck has much of a chance with any of them ... unless they're willing to take any P5 DC job for any reason. But that's not usually how it works in the coaching world, from my understanding. It's more about who you know, who you've worked for, who trusts you, etc.
EDIT: goofed on NIU
