When you import a catalog from Elements into LR, what happens to People Tags and Place Tags? Or are these just consider part of the keywords?
Information from your Elements catalog; including photo ratings, people tags, and other data; is preserved in Lightroom.
Named people will appear in the Lightroom Keyword list. Photos from Elements Places will appear on the Lightroom Google map.
You can turn on face detection in Lightroom from the identity plate dropdown menu but Lightroom will need to complete its own indexing. However the keyword tags help and it is only usually necessary to type the first letter of a name for a suggested stack.
Unsupported files from the Organizer will not be imported e.g. .gif