I don't think it will help to call now to check on availability - it changes too often for that to be of any worth to you.
FWIW, the end of August shouldn't be all that hard to get at the BCV or the BWV (unless your heart is set on a standard view or a guaranteed Boardwalk view at the BWV).
If you just can't stand the thought of using the waitlist or possibly having to move back and forth, just call 7 months prior to your desired check out date. Either you'll get it or you won't. You can even waitlist for all the days to come through at once if you like. It's less likely than if you waitlist for each day separately, but it can and does happen. If you waitlist for the enttire vacation, there is no risk of moving back and forth. You either get the waitlist or you stay where you are.
If it were me, I'd call day by day for the BWV reservation at the 7 month mark. (IMHO, the best chance is for a PV-Pool/Garden at the BWV, but you never know. Other views and the BCV could be available, too). If I had enough points to hold the VWL reservation until I was sure I had the entire BWV reservation, I'd do that. If not, I'd cancel the VWL reservation day by day to apply the points to the BWV reservation. If any days were not available when I called, I'd get on the waitlist.
7 months is a lot of time for a waitlist to work (if you have to use it). IMHO, there is only a very small chance that your waitlist(s) for the individual days won't come through. Again, August isn't one of the more popular times for
DVC members to use their points at WDW. Good luck!
Best wishes-