The cavalry is painted with a mix of some colours, sorry, no idea at the moment what ones. I'd say Foundry Drab 12 A isn't bad for the start but then don't take the B and C, it's too brownish, I would mix Drab A with something bright like VMC Ivory or something like this.
There is a image of the Storm troupers guy in the White Armies Osprey, you could use the same colour for the helmet and the top, the trousers need a bit more green like Foundry Phlegm.