With Micah, from your list, I like:
Whitt (either middle, prob McKinley) would myself go for Whitby/ Whitaker nn Whitt - Whitby here - but I can see the spunkiness of Whitt
Deacon (McKinley)
Sawyer (either middle)
Barrett (McKinley) “Bear” (unless within a couple of years of age and/or cousins that are more like siblings, cousins with similar names is usually fine - I have for eg nieces called Isabel & Belle and there’s no confusion or concern. But would only use with nn Besr being default)
Garrett (McK) - not my style/ doesn’t translate as well to where I live (nor does Barrett) but can see its appeal and how it works with Micah. Only use of OK with possible nn Gary.
Wyatt - I like Wyatt in general, just not sure re the repeat Y sound -MY-cah and WY-att? It’s handsome though for sure.
Warren and Grant are just a tad harsh to my ear.
Other names (that pair with Micah, and have that southern flair):
Levi
Jude
Joss
Jesse
Elias
Caleb
Hollis
Hayes
Heath
Ethan
Brody
Brooks
Everett
Callan
Orson (Sonny or Bear via meaning)
Jennings
Sullivan
Zachary
Shepherd