Magnificent work! Ogres are loved by Hive and there are many nice models, but this pack is consistent, detailed and works great in game! Already make me consider a few ogre-tastic ideas...
There are, however, a few suggestions my side.
1) The kilt clipping is very noticeable - in particular, on regular ogre whose bare legs are seen through the brown texture. Is it possible to assign lower vertices of the kil'loincloth to the leg bonеs? Might stretch weirdly, but it's better than completely static cloth
2) On Stonemaul variant, the loincloth is a bit too simple - just a red flat object. Perhaps you could rewarp it to have a more varied texture?
3) Increased detail calls for such thing as adding ears - they are quite visible on WoW and Reforged models, and earless bald heads look a bit too simple and plain compared to the rest of the model.
Thanks for sharing your work! Hope to see more from you ^^