I almost wonder if at some point they considered having Luke be physically alive to some extent. Like, maybe Luke could appear physically, as if he achieved an even higher enlightment than the other Jedi. But that wouldn’t explain why they would have to conceal his hand… Very weird. I don’t see why, under any circumstance, they would want to hide his right hand, unless they briefly played with the idea of him having some physical form and they weren’t sure how to depict his right hand.