Hi Donkey,
When I import pictures that were previously "Selected Pictures Export" the Original directory locations are lost because Export Selected Pictures does not save directory info. Album information is also not saved, but I Export Selected Pictures by album so when I import I create the Album to put them in. It would be great if Album and original directory info could be saved.
On the face tagging, once the selected pictures are imported, run face tagging on them and all the face tags will miraculous return. You will also get a lot of "2" and "unknown" tags that have to be cleaned up but that's easier than starting from scratch.
A trick I've learned is when I have a lot of pictures to tag with the same people I temporarily rename the face tag to "1", then when you select a face tag it appears at the top of the list and is easy to click on. When I finish I rename the face tag back to the person. Also when you plan to up load to Facebook use the persons Facebook name and they will be tagged in the Facebook Picture.