HA! Girl, I only have our wedding date booked. We aren't able to our book room and airline until the end of May (from what I understand, they can't do it sooner than 11 mos out).
When we decided to do a DW, we sent out emails and called people asking who would be able to attend and provided people with the estimated cost from our TA. So, as far as save the dates go, I think I am going to save some $$ by sending out an interactive email invitation (if that makes sense). By August, I would like to have the formal invitations in the mail. With that being said, my expectation is that everyone will book through our TA for the group rate and they can direct all of their questions at her. AND she said she would stay on top of people to RSVP in plenty of time so that I don't have to worry about it.
Is your H2B involved a whole lot in your wedding planning? Mine just keeps saying, "whatever makes you happy, will make me happy." I wish he had a little more to say about it all, but he is such a guy...