As far as I am aware, this would be a difficult one to arrange. There are very specific sites that Disney use for their weddings and doing it unofficially is very frowned upon. Doing it unofficially on a boat captained by a Disney cast member would not be a good plan. Of course, there is nothing to stop you repeating your vows to one another on the boat, but if you want officiant, flowers etc, you would have to go through DFTW. I have never heard of a wedding/VR ceremony on the 'Illuminations' cruise, but it wouldn't hurt to contact them and ask!!! Good luck!!