The issue with the immo not working might also indicate an intermittant pin/wiring issue for the rev counter fella, maybe there are some bad pin connections on the plugs, give it a good look over.
Have you got a meter as a simple continuity test on wires/pins would maybe tell you if pins have bad contact with wires, simple way is to just stick meter probe on wire down from the pin & other probe on the pin via a wire as cant stick on in end of the pin, then move the pin about where it joins the wires to see if it breaks the circuit on continuity.
Thats what I would check anyway as seems strange the immo wires failed for brief time & you also report rev counter issues as I've taken mine out on my old S3 loads times with no wire issues so think could posibbly be blessing in disguise the immo failing so it points you towards rev counter issue, just my thoughts anyway.