I'd go either a deep rust colour on the
GW base set or the mars red texture base paint. The red will contrast nicely with the green but because both suggestions are more on the dark brown side, the won't detract from the models themselves.
Saying that, here's what I did with my original
DG:
The 1st colour is a deep red (the old dark flesh) then dry-brushed with 2 shades of grey. The grey acts as a neutral colour, the hint of red as a contrast to the main armour & compliment to the spots of red on the mini & the green static grass as a compliment to the green so everything ties together. However I wish I'd used a more burnt yellowy-green grass as the stuff I've used is just to bright & vibrant
IMO.