OK, it's settled. There is such a thing as a Money Purchase 403b plan, so says Derrin Watson. He indicated that the reason they existed was that pre-EGTRRA there were benefits to a MP Plan with respect to that awful maximum exclusion allowance thingamabobber. So to the extent that there was a 403b MP plan out there, if that plan were merged, J&S would apply to those balances (hence my reference to the 205 above in Corbel's 403b Basic plan document).
He also mentioned that he has never actually seen one in practice . Finally, he mentioned that in the IRS's plan termination guidelines for 403b plans, they do make reference to "403b Money Purchase Plans."
This was all according to a voicemail he left me so I did not get a chance to pepper him with all of the logistics. But that was not necessary because his affirmation of these things was enough for me. No offense intended to the rest of y'all.