I think rather than "gesture" invitations, announcements, mailed the first postal day after the wedding, are the way to go. The "gesture" invitation seems to cause a lot of drama around here. One could always phone those people who almost certainly can't come and ask them personally if they would be able to come while making out the guest list, which gives you a chance to visit and involve them in the event by talking about it, and accommodate special needs if they can come. That would cut down on a lot of drama, too.
Getting a block of rooms at a negotiated discount is so usual that I am surprised anybody would mistake it. I would expect "as our guest" to be included if the hosts were paying. Once were were happily surprised when we called to make our reservation and were told our room charges were courtesy of the hosts.