That can also be linked which my "fan fiction" answer in "What animal was used in Neifirst's DNA?" post.
If Arisa has a clone in PSgaiden (I don't know how Mina was created, if she even was planned by Arisa or who the “Dr.” responsible for her creation was), musk cats in PS4 could also be Myau's clones (that would be the reason for their ability to talk and the concern, by at least one, to open bottles).
Also if musk cat's cells are the genesis of "NM series" (Cat-man-eyes-fang, Nei-1-2-3-2000, Fal, etc.), and if some "bio domes" are still active in Motabia (Seed), maybe some Dome/Plant in Dezoris started to release (or someone released/”saved”) Myau's clones previously created for the “numan project” purpose. That could also be the reason why talkative musk cats are refugee in Myst Valley. ~~~~ now you must be thinking "what a fertile imagination..."
Yes, I think Myau was unique!