I think I like you reptile dog best. The musculature and texturing look great - although the hips and back leg look a bit off. I think that the elbow joints on the front legs need to be lower or else this creature would have great difficulty running let alone walking.
I think that the eye needs a bit more definition rather than being a red dot... Also if you're orc is gonna ride him I think he needs to be a lot bigger.
As for the orc, whilst he is nicely modeled I am note sure about the Tarzan outfit or the bimbo boots. His musculature whilst very good looks a bit too human, I wonder that he should be a bit more orcish, with wirey legs and something of a belly? Why does he have his eyes closed, or are they very small and open? I also think that there is not much point in him wearing that T-Shirt though since there isn't much of it.
Well, that my little critic - hope it don't hurt...
Tickety boo and ta ta for a bit...