Look out for the commisars!

I did a small test on the skin of my commisars, to see if I really need to prime or not. 

I have painted several metal miniatures without priming them before, and I would love to avoid it.
I will prime the buildings and large models, but hopefully the regular miniatures will make due without. It should work as long as I spray them with varnish to protect the paint after.
So now I'm looking at pictures of commisars to see how I should paint them. I know I will have black uniforms and black coats but the rest of the colors need to be planned.