I think I'll go with this general scheme for my 'scratch' militia - keeping the hoods the same, but with variations in tops and trouser colour. This figure is wearing captured UMC gear (trousers and some of his equipment pouches). One aspect of my militia figures I haven't decided on yet is the goggles that some of them are wearing. On other test minis, I have painted these in the same green as the gun casing & with red lenses, to match my colonial androids. This is for a bit of uniformity, & to suggest similar manufacturing source. However, this looks quite toy-like, so I'm thinking I may go with gunmetal and various coloured lenses. I think the gun casing and lenses alone should be enough to visually link the militia with the combat droids.
As mentioned before, I am using Rebel Minis Sahadeen for my militia. These are 15mm scale figures mounted on 1p bases.