The monsters that X has with her I just don't really follow why they are there and thinking of changing them because I think they play an important part in another AP that the same group is playing in.
They just kinda seem like a throw away from what I am seeing. I didn't notice them coming back up in later books or anything (may have missed them) and for such a monster it seemed like a weird throw away.
Other than just leveling up some humanoid assistants are there any monsters that might make a good fit for this?
The main thing these contributed to my party's experience was added paranoia and horror over creepy shapechangers who could be anyone, upped the tension. To keep with that and the whole skin mas thing maybe give some of the cultists the ability to use skinned faces to polymorph into the appaearance of the sminmask? Add creepy flesh dissolve to rwveal the person underneath when killed and voila!
For the initial encounter you could use normal humanoids with potions of Disguise Self. To provide Java Man's sense of paranoia, hint that the bad guys have a plentiful supply of it; perhaps X has a magic cauldron which makes it easy to brew, though perhaps it needs to be seeded with the blood of the people to be mimicked.
But otherwise yes, you can substitute pretty much anything; they're just mooks with no other interesting properties.
Thanks for the replies.