When you book a reservation using the home resort advantage, that contract will remain locked, which means you have to use it first.
At 7 months, if there are any nights at the beginning or end of your trip availabe, you can book those with the CCV points, if you have any left, and then free up the BWV points you used. I have done that many times but I also didn't want/need those points for something else..
So, you may just have to wait until 7 months and hope if you want to guarantee you have your BWV points.
ETA: Now, one thing you can do...its risky, but worth a try, is to book the BWV now, with BWV, and then at 7 months, try with CCV to book new. if it is not available, then you could drop a few nights at a time from BWV, and hope to snag them right back. The risk is a waitlist might grab them...but I have done that too....it took time, but I accomplished what I wanted.