I actually like those silly metallic gel pens, maybe you could try colouring the shapes in with a lighter colour next time? I'm sure there are good ways to draw in colour with pens, I'm just not sure what those ways are! xD
Seriously though, these dudes are looking pretty badass, nice work!
I started looking at my H4 action figures or H4 game captures, but then added my own stuff from memory of past armors and just imagination and kinda made em... whatever. They are not any specific model.