Well, both greed and envy are about more than just possessions, and I feel the two are still too similar. I really liked the idea for Greed's power (kinda reminds me of Gilgamesh from Fate/Zero). 

For envy, though, what if he never was himself? He would have the ability to become clones of other organisms, though only one at a time, and not really having an own appearance. He would essentially have access to all the powers, but at the same time he wouldn't really have a power of his own. Thinking this might be a bit over-powered, though.