I decided on a scheme for the bases: Winter tundra. It is a little more work with the snow but it looks good and pops for color. Here is an example
I have all of the models for wave one in primer now, and I have started color blocking on the raider. My final color scheme is a medium brown base color for the armor plating. Specifically Vallejo model color mahogany sand. The metals will be Vallejo Model Brassy Brass with a dark wash. I plan on using Citadel foundation Deneb Stone as a second color and a third trim color will be an acid green that I have yet to pick out. More to come as I finish models.