1. I can't say for sure, but the issue is the wire being crushed by height adjustment.
2. Yes. I'm not sure what led to the issue, but now the noise issue without touching the instrument when plugged in has become nearly constant, making it unplayable.
3. Yes, they were swapped to isolate the issue to the pickup or the circuit on Mica's advice.
4. Basically, cutting the wire near the break on both ends, and adding new wire into the open section. Heat shink each wire individually and collectively, adding wire shielding where needed to help with any possible noise.
5. Yes. At least for a new one, or wait for a used one to become available at a significant reduction in cost to me.