The sensor in question sounds like the clutch switch to me, was it mounted on the clutch assembly it self so that when the clutch is at rest state it presses the switch?
Yes that's the one
I don't think its normal for the pedal to wobble and it might be worth getting it looked at, you definitely did all the bolts up on it didnt you? It does of course depend how much its wobbling and if your feeling it with your foot or hand.
Yep everything back in place as it should be and tightened up, i didn't do it myself but i double checked it. I can feel it wobble with my foot, i'd say it wobbles around a cm either way, it's not moving side to side on the main bolt though if you get what i mean.