Much refactoring of spawns and Enchanting Table, plus cow tweaks.
Mooshroom now from mushroom soup (alternate path to leather if no cows)
Dragon now spawns from striking dragon egg or end portal with enchanting table snowballs.
If portal, dragon goes to End. If egg, dragon will immediately appear and blot out egg, and you get another by killing that dragon.
Other spawns: blazes can spawn from striking lava or fire just right, endermen from bedrock, all spawns check harder to see if they are going to suffocate. If so, you get a lightning entity (sound and flame), not the mob.
Horses from flowers, etc. This requires some dexterity as just hitting the flower/lava/etc will produce a dirt hit. Dirt/grass/sand/gravel mostly produces primed TNT, making enchanting table snowballs more dangerous. Usually witches, apart from the special cases.