Hey Erik,
About the base colours, choose what you like. darth tater painted them in a purple base colour, I for myself used a dark brown. As this is a fantasy setting, it's totally up to you.
I chose darker earthy tones for all my minis, because I come from the Warhammer corner, where all my lizards are already super colourfull, and i wanted to try something different. So I use the brighter colours only for armour and marking.
hope that helped a bit, maybe keep browsing the painting section a bit
cheers