Buy where you love to stay, you will always get what you want, when you want it.
But only if you can plan 11 months out.
And only if you know that you would be disappointed if you cannot get exactly the resort you want when you want.
Since I wanted to visit all resorts over time, I decided to buy the cheaper resort where I don't mind to stay if it is my only possibility (SSR, convenient for DTD) and try to visit over time all other resorts.
However I don't have children so I'm very flexible with my dates and I can travel seasons off peak for DVC, so I think that booking at 7 months I'll be able to accomplish it.
However as the total number of members increase, competition at 7 months will be bigger and bigger over time. I've often seen resorts with availability at 7 months and nothing more 1 hour later.
For the resorts you asked about:
- BCV: it is small, so it's hard to get it at 7 months, but not impossible in low season
- BWV: it has two booking categories very hard to get, BW view and Standard view (very cheap points). Garden view is often available at 7 months
- BLT: hard to get a standard or theme park view at 7 months, Lake view is easier
- but all three are very hard to impossible to get from late September to mid January (due to Food and wine and holiday season)