These ideas sound excellent. All sorts of animals, especially canines and felines, use their tails to emote in a variety of ways, so it would be invaluable if we could get to show off our feelings with our tails in an animal-based roleplaying/chat game. Moreover, people have characters of all sorts of fur lengths, so being able to select their texture to express that and make them stand out would be like a dream.
I also really like the idea of people being able actually see the sort of tail your character is supposed to have rather than a bare butt or something wildly different, and getting popular community-made model mods turned into vanilla content seems like a great solution for that.