We have stayed at a one-bedroom at VGF and a two-bedroom at BCV a few times. Any two-bedroom is going to give you a heck of a lot more space than a one-bedroom. You'll like being able to put the kids to bed in the bedroom, while you have the living room at night and in the morning. A two-bedroom also gives you a second bathroom, which is a big deal when getting ready in the morning.
VGF gets you close to the Magic Kingdom, and a Monorail ride to Epcot. BCV gets you close to Epcot, and a Skyliner ride to Disney's Hollywood Studios.
The BCV pool (called Stormalong Bay) is very popular. But its layout is complex and difficult to find seats. If your kids are older, they probably will enjoy exploring. But if they are younger, you might have difficultly keeping track of the 3 of them. (BCV also has a small quiet pool.)
VGF has 2 mid-sized pools with more seating, but even those can be hard to get during the busiest part of the day.
Both resorts are lovely. I suggest you look at online photos and decide which one appeals to you.
The thing is, both VGF and BCV are very popular, while October to December are the most popular months of the year for
DVC resorts. The two-bedroom at BCV is still available, and so is the one-bedroom at VGF for almost all nights. But the problem you might run into is finding someone to rent from. To get those, you're going to want someone who can book beyond 7 months at those 2 DVC resorts, and points for those 2 resorts are very much in demand. You could get lucky renting those at 7 months, but it will be more difficult for those 2 DVCs.