I really like that ogre! Quite simple but effective conversion. Perhaps you could add some tattoos or small bodypaintings (eg. markings of ownership, as if he belonged to a certain Sorcerer or other potentate). But why not base the mini before painting?
I also like the idea of using WoC for Chaos Dwarfs. A friend of mine will do the same, although the Dawi Zharr will only be part of the force (the Marauders, mainly). Interesting idea.