I did actually skim through other apps that've been linked in the thread, and I didn't see one that seemed like a direct competitor with the combination of emoji + automatic face detection. Granted, this could be me defining the market too narrowly, and many people might get by without one of these just fine.

(My own App Store searching turned up one called Face Blur which seemed to have emoji as an option... as a subscription, which seems like a non-starter.)