I'm developing something for you that does what you're looking for. I called it ZeroGravity. When a spacesuit is equipped the player experiences no gravity. Take the space suit off and gravity is enabled again. This is map-wide and active all the time. The movement controls are very similar to what you describe and after initial testing, what I've outlined above is working as well as water detection. I'm just now working on oxygen consumption while in a space suit. I'll keep you posted.