MY HUNCH PROVED CORRECT, if a few weeks late. I dug into my trunk this evening upon returning from work, and lo and behold, I discovered my old work IDs and transit passes deep in its recesses. Moving the folding chair must have dragged out the PATH pass and exposed the rest to plain sight.
I wouldn't have even dreamed the passes could be my trunk! In trying to retrace my steps, I can't see any context in which I would place them there, short of being zipped up inside my work bag.
The PATH passes I can use, because they have many remaining rides still on them. The September 06 NJ Transit pass is good for the rest of the month — all of 2 days — but I bought a weekly pass already to replace the monthly, so it's superfluous. As for the work IDs, after more than 20 months, they're actually pretty beat up and faded, so I will surrender those at the office and rely on the new ones I had made up.
Next mission: not losing the replacement ones!!