Very nicely done! The Reaper MSP Dark Elf Triad is very good for representing black, but so are some other colors of their MSP line. MSP Grey Liner is one. MSP Noir Black is another one, which isn't quite black. MSP Ritterlich Blue mixed with a little MSP Red Shadow creates an interesting shade of black.
The NOVA Corp figures are pretty good to use as COGs. I would of never thought about using them. I use modified DreamForge Eisenkern Stormtroopers as Exo-Armor suited troops.
Great work all around.