Created an interface called "frozen" for SF to look at the pre-deletion content, in search of reasons for the orphaned users. I've also added a "Linked titles" field to the Properties table in that interface; I should probably do the same thing for the live db. Lots of work today trying to figure out why there are so many unlinked new owners; looks like some titles didn't get created when they should have been, or something along those lines.