i think this is pretty normal. they just want an idea of what other options you might be considering. it's also a way to understand what your research interests are - so if you tell them a bunch of places and POIs that aren't all related in some sort of way, they might think you're unfocused or just applying to apply etc.
I think most if not all invitations have been sent. POI emailed to formally invite me to interview and told me someone would be in touch with details. Personal email from someone on staff came with details about travel accommodations and reimbursements came after.