Hello.
I am still seeing plenty of baby cows, pigs, sheep in the wilds. They are killed periodically as I travel, and I still see them again when I pass through the same areas.
I have nothing external to the game installed. Minecraft pe from the App Store, and that's all. No devices jail broken, etc.
So I dug a perfectly straight tunnel through a mountain, and ran backwards. Wolves will "pop" in front of me to keep up, but do not appear to be replicating when they do so. However, I quit to title at the far end of he tunnel and.... Just got four new buddies. They were NOT there before I quit (narrow, long, well lit tunnel that I had been hanging around in for while), so they couldn't have just wandered in from the wilderness, unless these are special spirit wolves that can pass through solid stone blocks. Which would be super fly if they didn't spirit mob me off cliff faces.
Killed all wolves except one. Walked around the village. No duplicates. Cut across country for five minutes. Already got two new wolf buddies. Unsure if they are populating because I walk faster in open ground, because I am crossing water (hard to avoid in the current terrain) or just over time.
No other mobs appear to be self replicating. Only the wolves. I am going to experiment with walking slowly and avoiding water crossings.
Forgot to note, this is in Survival mode.
I will note that mobs seem to spawn more quickly if the difficulty level is set higher, though I am sure this is by design.