I have found and fixed the leak(s). The bottom line is that the sunroof seal was leaking because the fasteners holding it in place had somehow become finger tight. The reason the seal was even an issue was that the two front drain line bungs were clogged with a smelly slurry of wet organic matter that can only be described as "gunk".
The signs that alerted me to this issue were soaking wet floormats (both fronts) and wet seats. Upon further examination I found water on the A-pillars, visors, and headliner (dripping out of the card holder).
After dropping the headliner, I poured water into the sunroof tray and immediately found it to be dripping heavily from the seal. This is the seal between the composite sunroof tray and the metal roof.
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I checked the bolts that secure the tray and they were literally finger tight. Not just one, but every nut and bolt on the front half of the assembly (two black bolts and four gold nuts). Btw, the red drain line can be seen in the first of this series.
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After applying blue loctite and tightening those, the leak stopped, but I noticed the tray still wasn't draining. This turned out to be the only reason the seal issue ever mattered at all, as normally the drain lines prevent any water from accumulating.
SfmDRuT2