We sent out STD postcards/magnets from Vistaprint to everyone, even those we knew couldn't make it.
We are now in the process of getting together invitations, and I think we will send out really nice invites with packing lists and hotel info to those who have RSVP's yes and we know are joining us...for the remaining group who have RSVP's no or said nothing at all I am thinking of doing a very simple invite, with a letter included regarding travel and hotel info in case they change their mind.
Our AHR is four months after we get home from Cuba, so we're gonna need to do a whole new invite for that, which we will send to everyone.