Jon - I haven't had your experience, but I can comment.Broken leads are usually caused by excessive excursion.Your 2 volts AC at the tweeter and woofer with a 60Hz test signal is improper. Tweeter should be near zero.Caps and resistors usually blow open, not short. Hmmm. Shorted feed cap or resistor would cause direct feed and tweeter destruction.If your XOs are on PCBoards, the short might be in a trace, not component.
Rob Gillum at Coherent Source Service might help troubleshoot
Rob Gillum at Coherent Source Service might help troubleshoot