That was a fantastic video, made a lot of sense, will look more into that point of view of emotion over likeness.
Another tangentially related idea I had to cutting costs/production time, while not necessarily related to monster girls, is skipping over the voice synthesis and chatting capabilities for pure voice/emotional recognition and expressiveness.
A mute, until sufficient software can be developed, but one that understands and can communicate through body and facial language. So being pointed into the direction of expressiveness opposed to pure likeness is actually a big helper on that front, thank you
The one of the best parts about deciding to create a 'monster girl' is that you can just throw on unnatural stuff like tails or bird feet (you could even go as far as creating a chimera-type if necessary), as you've noticed, to help push things such as mobility and balance farther easier than it would be with human appendages, which is the primary reason I'm aiming for it myself.
As long as I can create something I can love and semi-interact with (which likely other people would be able to), the parts can be whatever. Monsterization out of utilitarianism or something like that