The most interesting thing that I've observed about Mei-Ying's animals has been what they don't do - they never fight.
Among creatures that have been domesticated for generations like cats or dogs, that's normal, but there's a reason zoos keep their animals in separate enclosures. Certain instincts are hard to curb, and there should definitely be more disputes among such a diverse group.
Mei-Ying has even integrated a herd of herbivores into her army, as their thick hides have proven resistant to fire and explosives. Yet despite being surrounded by carnivores, they remain untouched. It doesn't make sense.
That's not to take anything away from Mei-Yin. She works hard to treat and train her animals well. She's not bad company either, at least when she's not mute and I don't go full biologist. Sometimes it's felt like speaking a new language, but it's been kind of refreshing.