Wiring Z-stop directly to hot end and aluminum bed / spacers
Aluminium is conductive, but aluminium oxide is not, which is just so what there (unavoidably, since aluminium rapidly oxidises in air) happens to be a thin layer of on top of your bed. The coating is very thin, but it might foul your plans. It would work better with a sharp probe (that can puncture the layer) than with a 3D printer nozzle. You should be careful, because your probing method might be unreliable (which could cause the nozzle to crash into the bed).

Wiring the endstop 5V directly to ground will create a short circuit which will damage your printer. You should use the third (signal) pin and ground instead.