Is there a question in there?  I think the concept you've put forth would look pretty awesome.  I'm not as much of a fan of just basing specials/characters fancily though, I like a consistent base style throughout the army.  That isn't to say that the higher profile figures shouldn't have 
better versions, just that I personally prefer consistency in bases.  Maybe if the grunts had rocky bases with less or no cracks, maybe something easier to do by hand but in the same general colors to tie it in.
 
 
Scroll about halfway down for what looks like some kind of acid base.  Is that vaguely what you meant by green for the resin lava bases?
 
 My google-fu is too weak to find purple dark-energy bases.  I'm sure it's been done (and sounds cool as hell) but I don't see it when I look!