Mutant abilities are present because of the X-gene in the body. So, mutant powers are there because of the mutant's physiology. Elixir copied Wolfsbane's son's physiology and change her's accordingly so she can survive the pregnancy. This means, Elixir copied Asgardian DNA and is able to change another person's DNA according to the one he copied. Not to mention, he also has the ability to heal/repair the X-gene (re-unlocking Wolfsbane's mutant abilities). Since mutants are now coming back and the effects of M-day should have been gone, can Elixir now restore power to depowered mutants? Alternatively, can he change up his physiology so he can have any imaginable mutant power? By obtaining a few samples of DNA, can he use those to clone someone? Can his powers affect microorganisms?
If yes are the answers to all of these, then Elixir should really be labeled as an External or a god.