October through early January are the most popular times for BWV/BCV. Food and Wine festival makes this a very popular area to stay. Then Thanksgiving, Christmas decorations/low points of Early December, Christmas, following through the marathon. A lot of owners own specifically for this time of year.
However, there is usually SOME availability at seven months. And using the waitlist can help. Remember however, that this time of year is not only popular to stay at these resorts with BWV/BCV owners, but OKW/VWL/HHI/VB/SSR/VAK owners also find the idea of the Epcot resorts attractive during Food and Wine. So the competition for the remaining rooms available at seven months is fairly high.
If you want to try all the resorts and travel at different times of year, most of the rest of the year you'll have an easier time with availability than October - early January.