Awesome. That's a really scary, weird monster. Even for you, VT.
Some points I'd like to see cleared up. First, the discrepancy in the creatures' speeds: the Momeh flies at 50', but the mob can only surge around at 20'. Can the Momeh fly away from the mob, or is it linked to them (as the description suggests)?
Second, the mind-consumption works when the Momeh successfully grapples an opponent. Obviously, the key is not to get into grapple range, but if you do, it makes a touch attack, starts a grapple, and instantly has you making Will saves. I feel, at least, the creature should have to take an action to establish a Pin, before it can consume your mind- especially since it instantly, almost irreversably destroyes the PC.
Third is the obvious problem that incorporeal creatures don't have physical bodies with which to grapple. It looks like you're just ignoring that here purposefully, which is fine, but should be stated explicitly- or, as in the case of the Spectral Lurker, give the Momeh an ability to use its hands as Ghost Touch weapons as it wishes.
Fourth, can True Seeing or other magics get around its Born of Dream ability?