The same idea for any pet/summoning champ: when the pet/summoned unit deal dmg and the owner has lifesteal or spellvamp, does it heal the owner or itself? The only example I know is Mord, the dmg dealt by illusion from his ult will heal Mord.
ummmm.....hmmm....I feel like the Revenant's damage would count as spell damage. And if that's the case, it would proc spellvamp, but not lifesteal
In general, pets don't heal their controllers; they're separate units. Mord is an odd corner case; he's definitely healed by the mark DoT, and the ghost's autoattacks charges his shield passive, but I'm almost certain that it doesn't trigger spellvamp or lifesteal. It triggers on-spell effects just like Tibbers does, so it shouldn't trigger spellvamp on its autos. Mordekaiser's revenant will only heal itself if the original target had some way of doing so (Nasus' passive, some item, etc.)
Well I'm pretty sure the ghost thing does physical damage, so it wouldn't work with lifesteal or spellvamp. I think it would work with 
though.
