I don't think there are any pre-made materials for this kind of conversion, so I'll give you some guidelines.
Combat Conversions
The biggest problem you'll run into is Attack and Damage are resolved in a single roll. You'll need to do your best to balance the dice pool your example zombie is going to have in comparison to its damage. I would also say that J Grim's suggestion about looking for pre-made zombies is the way to go.
Spell Conversions
Edit!
I didn't notice "CtL" in the original post. This can be done in changeling with Contracts and Pledges as well. For Knock, as @Frew mentions in the comments, this can be done by entering a pledge with a lock, though I think you'd have to finagle it to work with every lock (I can't recall if you can enter a pledge with all locks since that would be more the purview of a contract, but you could enter a pledge with a specific lock on the fly to duplicate the spell).
For Speak with Dead, there's a Darkling contract Shade and Spirit which does the same thing, though it has some restrictions.
Fireball is probably Elements 4...
Overall you can paruse the Contracts on the White Wolf Wikia, there are several which duplicate spell effects.
The problem is here that Changelings aren't much adept at spell crafting so much as they have several spell-like abilities gained with their contracts with various things, which makes it harder to get access to spells than it would be in a D&D setting.