Oh yes, he'd do something over the community first off, to gain her confidence, since it's all audio/video there. And since Envy is shown to canonically replicate inorganic material (ie, changing his arm into a sword) I don't think it would be a far stretch to replicate automail, but you're right about it being difficult to pull off accurately.

Oh ho ho ho! Like putting a collar on her and parading her around in skimpy clothes for all the world to see?