I mean, all of that sounds pretty do-able if you put the work in. Ponies? Not a problem. However in my experience the more sophisticated the animal behaviour in my modded Minecraft the less I like it.

Vanilla Minecraft cows produce milk if you click them with a bucket to put the milk in. Convenient. Some packs though provide real cattle. You need a cow, and a bull, and they need to be together with plenty of good food, and then the cow becomes pregnant. So you wait until she gives birth, steal her calf and now you can get milk. Or, you can decide actually you don't need milk that badly and the cows should get on with their lives unmolested.

I don't entirely sympathise with the people who wrote Better Than Wolves, but, you know, their water powered machinery is probably better than wolves considering the effort that went into each feature...