I like the 'Medic' costume the most. I prefer the use of accessories and belts to create visual flow and really sell the the concept of this guy using contraptions strapped to him to embody the lightning element. Something about that little console hanging at his hip sticks out to me too.
I'm not sure about the hair though. Looks too styled and well-kept for a maniac that doesn't make the concept gel together, in my opinion. Maybe try more crazy or disorganised hair styles? You could look at the characters from the Borderlands series for more ideas. Good work so far, though.
