I like the full, themed Harad army.
As for the Mumuk, probably prudent to keep him from the main force to minimize surprises, but those things are a beast. I expect to be playing AGAINST one soon in our WotR Tale of Games.
I think it's going to rip me up pretty good, and that's just one. You're talking about having two on the table.
The amount of damage that they cause in a Fight against everyone involved is really vicious. It really makes you want to just sit back and shoot at them with a massive amount of bows or siege weapons and that takes those out of the role of attacking the rest of your Harad army.