Azog and Warg = 3 3/4 - I think.... It looks like this one has no ankles so that is why I am suspecting as much. I just don't recall Azog having an arm when he rode the Worg. Maybe he rode a Worg at the beginning of the movie before he lost his arm.
The pic with Azog, Radagast and Bolg should all be 6 inch figures. I say this because Bolg has ankles whereas the 3 3/4 inch version did not.
All the dwarves should be 3 3/4 as well. No ankles plus Grinnah is behind them (I am pretty sure there has not been a 6 inch Grinnah). Dwarves look awesome - lovin Bombur!
Oh, and of course there is the mention of PLAYSETS!!!!!! Awesome!!!!!! But really, I think early on, Thorin/Goblin King was considered, or described as, a "playset".