Bob O
I went around this same time last year and we started waited about 30 minutes prior It is well worth it for The Christmas Fantasy Parade.
We always queue up early about 45 minutes for Believe... In Holiday Magic" Fireworks Spectacular. We always try to strategically place ourselves underneath a "snow cannon" or machine that dispenses the baby shampoo they shoot out into the air to mimic real snow. My daughter loves it as I am sure you and your family will. I have never been to WDW during the holiday season so I am not sure if they have something similar there. You can easily spy one of these above main street, just look up. We literally stake out a spot right in the middle of mainstreet. Then after the parade is done we stick around and take pictures. (Everyone else usually files out. ) We eat ice cream or other treats on mainstreet on the porch with chairs. Some of us even just sit on the stairs of the porch. After we finish eating we start taking pictures. Last year security even took pictures for everyone in front of the tree and the little xmas display they had out, I believe a carriage or something in front of the tree (i'll have to check my pictures) Anyway they were very nice and they only asked us to leave about an hour after the official closing of the park this also when the main street shops close for business.
Hope this info helps. Of course I am just giving you advice on what has worked for us in the past so you never know you just always have to keep your eyes and ears open and make the best decisions for yourself. We just went last month for instance and thought the parks would be deserted in the middle of the week but there were actually a suprising amount of people in attendance.
Anyway above all have fun. Your family is lucky that you are trying to plan an easy stress free vacation. I know you are leaving in about a week but if you and your family like the rainforest cafe I would suggest you join the Safari Club. I have been a member for a year now and I would highly recommend it as it puts you ahead of the line (first available seats) and also rewards you periodically with gift certificates. It is also good at all Landry's locations. We have used it at Joe's Crabshack in San Francisco and Anaheim and also at the Crab House in Orlando.
It is 10% off your entire bill or a free chef's appetizer, whichever you specify. It costs $15 to join -- you can enroll at any Rainforest Cafe or call 800-5LANDRY, option 8 and get details about how to enroll by mail. Your benefits include priority seating, guaranteed reservations when made 24 hours in advance, a $10 certificate good toward your next meal at the Rainforest Cafe and 10% off your meals (including meals at other Landry's restaurants, like Joe's Crab Shack). On your birthday and anniversary, you will usually receive coupons by mail for $5 off. The Rainforest cafe is in Downtown Disney
Good Luck Bob O
MandaMom