Seems like the whole reason why customization like this is restricted is so the animations line up properly. I'd imagine customizing height throws a monkey wrench into that whole affair with how many points of interaction there are in some animations (ie, not just the pelvis needs to be lined up, but hands, face, etc.).
I'd imagine it's also the reason why only certain pairings can have certain animations. Shey's model is taller than other women. Jadeen is roughly the same height, so they share animations, but they don't share animations with Maya, who is shorter, etc.
Hopefully they find a graceful solution.