Sounds pretty good, also maybe they can muffle the sound (like how it happens when you are underwater) as there is no sound in space, though i got no idea if it applies
Excellent! However, you'll need to balance fall damage as well, since I think it's based on distance or time spent falling. With lower gravity and high jumps, you may kill yourself far more frequently with falls.
Low gravity was in until the jumping dungeons were made, and they decided to cut gravity rather than use a different dungeon style
