Argh. So, in the end, no joy, but I learned a few additional details that might be useful for others in a similar situation.

1) The transfers are intended to be only for Platinum members as it was in FPC. After explaining to them that I was only no longer Platinum because there was no apparent reason to maintain my loyalty through the conversion, the agent was willing to do it for me anyway, so YMMV.

2) The real sticking point was that apparently the transfer happens on the FPC--not Accor--side. That means they need to transfer from one previously FPC account to another. Sadly, my wife never had an FPC account, so even though I had registered her for an Accor account, apparently it lacked the faculty to receive certificates.

C'est la vie.