While I feel inadequate grading your work I'll give it a shot:
Sig A: 5/5, 750k - the text might stick out just a little stylistically, but good overall
Sig B: 4/5, 600k - my least favorite, BG work is great but not a fan of the bottom banner
Sig C: 5/5, 750k - only real comment is that "Ricky Maddox" is super lightweight and gets a little lost, then again a heavier font might be overpowering
Sig D: 5/5, 750k - everything is pulled together really nicely, might pull the smoke off the Z just a little but I'm nitpicking