PVC insulation on wires does work in our Coolants, however what will happen over time is that they will be stiff as the plasticizer is leached out of the PVC. This does not affect the insulating qualities of the PVC insulation, however the wires may lose some of their flexibility. For most situations, this is not impacting on the performance of the device since most wires are bound in place by the geometry of how the device is set up.
Regarding TIM, you can are correct that you cannot use hydrocarbon based thermal greases as they will degrade over time. However, I would recommend you see this post
concerning the correct types of TIM to use with all of our coolants.