Okay, just picked my car up from the dealer. Here's their assessment:
They referred to SSM15934, the text of which reads as follows:
15934 MUSTANG- COLD ENGINE LIGHT TICKING/RATTLE
Some 2001-2002 Mustang GT and Bullitt with the TR3650 manual transmission may exhibit a light ticking/rattle noise while driving after a cold engine start. The noise will typically occur between 2200-3500RPM under light throttle (1/8 to 1/4 open) while driving. The noise may last a few minutes (depending on temperature). The condition is due to the combination of the light load operation noted above, and the normal piston to cylinder bore clearance present in a cold engine. To service, verify condition and reprogram the PCM with the latest calibration via the just-in-time process if your WDS communicates with Fordstar. Also obtain calibrations on the Ford professional technician society (PTS) website - select 'WDS' and then 'PCM REPROGRAMMING' and click 'Instructions' for downloading.
This pretty much describes my car to a 'T' except I would have referred to it as a "COLD ENGINE DEATH KNOCK" rather than a "light ticking/rattle" lol. So basically they're saying it's a piston slap.
The only thing I've noticed now is that the engine idle is hanging up a bit before settling down but that might just be a re-learn issue. I'll just short shift the thing at 2000 until it warms before beating on it I guess. If it does die later, at least I've got a record of reporting it early.
Also, FWIW, no mention whatsoever was made by the dealer of my FIPK or pulleys in regards to warranties...