If a mob is holding a shovel, it should be able to control a boat
If a mob is in a boat and is holding a shovel (in either hand), and there is no player in the boat with them, they should be able to move the boat, using the shovel as an oar.
This would be a fun way to move around any mob that can pick up items .
Also, if fishermen villagers sold shovels for emeralds, they could move in boats if a nearby player is holding an emerald.