One thing you might want to consider--it's a little delicate, but...
Your mother obviously knows about your honeymoon plans. What are the chances that she could suggest to some relatives or freinds that you'd really like to stay at the Polynesian for your honeymoon, and ask for people to give you Disney Dollars for shower/wedding gifts to be used towards the cost of the honeymoon trip? If you knew in advance that you were going to get a few hundred dollars (or more) in Disney Dollars, you could book the Polynesian.
Last year I threw a bridal shower for a friend who was trying to get married on very tight budget, and on the invitations it was suggested that the "theme" was gift certificates to places that she was using or could use for her wedding needs--a hair salon for nails, the florist her flowers were coming from, Hallmark for misc. items, etc.
She got enough in gift certificates that she was able to have some of the wedding budget left over, and she was able to apply that towards an upgraded cabin on the cruise they took for the honeymoon.
Either way I'm sure you'll have a wonderful trip, but it's something to consider.
Anne