At this point I'd be very confident that the waitlist will work for you - I would, however, check in with MS in a few weeks if you have not heard anything by that time.
We had the same thing happen trying to get a GV at HH for next summer. I had already gotten the first 4 nights and still had 2 more to secure. I called right at 9:00am and there were none left. I did call the next day and was able to get the final day - but now we had 4 nights - a 2BR/Studio - and one night. I asked to go on the waitlist. About 2 weeks later, I received a confirmation for the missing night and called to verify that we now had all 6 nights.
If you caan, go ahead and reserve the 2BR/Studio for the last night - but stay on the waitlist. I will be very surprised if the waitlist does not come thru for you.
Thanks Doc. If I go ahead and reserve a 2BR/Studio for the last night can they automatically cancel it out if the grand villa comes through. I am borrowing points for the last night of the reservation. If not I could maybe reserve at another home resort. Also, do you think that my elevator building confirmation that was set up through special services will be ok even though my last night was not available yet? The CM yesterday went ahead and put the 3 nights for me since he thought I would get the last one today.