[Endoperez]

The artifact Tartarian Chains has 'Enslavement'. It transforms commanders into units, but it might be enough.

The ghost wolf might be called a phantasmal wolf, similar to phantasmal warriors etc.

Ethereal units look different than normal units even if they share the same sprite, so if you plan to make an ethereal wolf you could perhaps use the sprites of one of these:
normal wolf, dire wolf national of Vanheim/Jotunheim, winter wolf, a black dog from some mage who changes shape (I think Oni kings/Shinuyama/Jomon can summon one) or a Cu Sidhe of Tir Na Nog.