@MG3G, you mentioned that you might drive in an earlier post. What happened to that? It seems to me that you have unique considerations between the size of your family and the need for you to use a
scooter to get around. I know it's a long way from BC (!) but it might be more comfortable for you to have your own car in Florida. Another thing that occured to me, I wonder even if you found a place that has a shuttle it may not be able to take your scooter.
If you book a condo/house, I like the area just south of Animal Kingdom. There are lots of restaurants in the area plus a Target and a Publix grocery store nearby. I would suggest that you look at VRBO for a house/condo or windsorhills.com and search for a minimum of 4 bedrooms and 10 people (to avoid couch surfing). I put in dummy dates (2/1/18-2/22/18) and found a 4-bedroom townhouse for 21 days out in Four Corners for $1102 all in at the Regal Palms Resort/Spa (about a 20 min drive to WDW). You can pay a bit more and get a house with a private pool in the backyard. Since you're looking to stay for 3 weeks I would pick a few places you like (even those that are too expensive) and negotiate with the owners. Many owners will take less to guarantee that they have their house rented to 3 weeks straight. Good luck!