Is it possible to altar/edit character movements such as jump height, velocity, etc? Also could I disable keybinds such as W or the Up Arrow?
You can use certain roblox objects to affect jump height, similar to how the gravity coil does.
I'm not sure if you can disable those keybinds, but you CAN bind to them, at least to W.
There might be a way to override whatever roblox does with them and cause your own code to be used.