For Vash I would go with Ian Somerhalder. I think he's got the right combo of rugged looks and boyish charm. He seems able to play overconfident characters without making them total jerks, and that is what Vash would need.
I'm.... actually someone who sorta' dislikes pictures of RL actors/people photoshop'd onto ingame stuff, just has always looked... I dunno. But the ones you guys have done look awesome! And I was super bored and haven't much to do at the moment, so... thought I'd revisit Coby and Soa'.
This took me forever to decide, firstly because females that are 7'6" tall pretty much do not exist and would have to be digitally or creatively editied. Secondly, playing a rubber forehead alien means lots of makeup to hide who the actress would be anyway.
But, I chose Jaimie Alexander (as Lady Sif) to play Kozath, mainly because I think she has the right facial structure.
Turned out pretty good, but I do not really want to put any more time into it. Also, Kozath smiling! But I'm not sure how I feel about the mouth.
Also, being colorblind makes matching skintones horrible.