Modern...Fantasy?

I got a new project to complete for a client, and it's a strange (unusual?) mix of modern/post apocalyptic sort of stuff with fantasy races.

This is my first test sketches:

The races are gnome, dwarf, elf, half-elf, orc, robot, human, lizard-man, halfling.
Classes are mad scientist, gangster (pimp?), punk drifter (wasn't sure about this one), celebutant spokes model, cop, mad max/wasteland survivor/bounty hunter, Navy Seal, Starfighter Pilot.

I can say for sure it's stuff I usually don't draw. At least not in this sort of context.
Challenges are good though! 0: Let's see how I do!

Now for self-critique and such: I personally like the dwarf, the elf, and the orc best. tbh, the robot turned out not bad for a first try...though it needs a lot more work.
These will be all coloured, so I will have to pay attention to vary the colour schemes a little, making nothing seem repetitive.
The ones I am NOT happy with are the gnome scientist, the starfighter halfling, and the lizard navy seal. probably because I am too clueless about the 'classes' to add a distinct character? =/ hmm.....

Anyway, less talking, more practising. Thanks for looking!