I'm not sure if scheme is the primary reason that those guys weren't brought back. More likely, it's that they were over-paid. Church got $6+ mil, Carr got $6 mil, Claiborne $5 mil. for 1 year, McClain nearly $4 mil. just in his 1st year, etc. Additionally, each has glaring limitations. Church was limited athletically in coverage...as is Carr. Claiborne began to play pretty well, but has a damning injury history (to inc. starting just 7 games in 2016), & he wasn't as effective switching between coverages. Wilcox was at his best last year...but in a more limited role. McClain finally stayed healthy for most of last season, but saw his playing time dwindle towards seasons end.
Marinelli has become somewhat more versatile. He'll attempt to switch between zone & man...and has also begun to occasionally employ more odd fronts. That's more the prevailing way in the NFL now...as is many defenses being in sub-packages more than their base D.
In terms of talent needed to run a so called Tampa 2 hybrid...yeah, talent obviously helps, much like Seattle. Then again, you need talent to run any scheme. Hence teams like the Broncos, Giants, etc. spending big on their defenses.
In his last season with the Bears in 2012, Marinelli had very good talent on every level: Peppers was the 'War Daddy' on the D-Line. Briggs & Urlacher were at LB. And he had Tillman as his top secondary player. That said, lesser players also enjoyed career years: Israel Idonije (7.5 sacks), Corey Wootton (7 sacks), & Melton (6 sacks), on the DL. Tim Jennings (9 int's) & Major Wright (4 Int's), in the secondary. His defense that year was top 10 in everything, to include 3rd in points allowed & tops in the league with 44 takeaways.