David Schwimmer.
He’d be Sgt. Carter while Pyle would be…
Vincent d’Onofrio, who else? 
Can’t believe that no one else said it!
I think it would be just as hilarious as the 90s remake of Beverly Hillbillies.
Best wishes,
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This cannot be ignored - McBrayer would be perfect!
In Capt. Sobel mode for Sgt. Carter? Could work.
Jemaine Clement as Gomer
Jeremy Piven as Sgt Carter
How about John Favreau (using his performance in The Replacements) for Sgt. Carter?
I don’t know about Sgt. Carter, but I think that Tony Hale (aka Buster from Arrested Development) would be the perfect Gomer Pyle, at least in looks. Whenever he was in his army fatigues on Arrested Development, I always thought he looked like Gomer Pyle:TNG.