>>96351079
these three are very distinctly mk. X phobos armor, so avoid those. the robo skull head should be fine for an IW character, but I don't think I'd use it for any other legion. the bare heads are just bare heads, so shouldn't be a problem. the bottom three are basically just gas masks, so I think you could get away with those. you could maybe fill in the slits on the face plate things on the two on the left to make it read less as primaris, but so long as you paint it as generic gear (black/metallic/whatever) instead of part of their armor, I think you should be fine.

I don't really think any of those bits look particularly good though, so I'm not sure why you want to use them.