We cannot yet predict what the nosie level from DD will be, but I'd say it sounds to me like you're "leaning" toward the VWL. Certainly not a bad choice, especially if you like quiet in the evenings. Your assumption that SSR could be noisier due to DD proximity may be correct. I know that folks were worried about that same thing when BWV was being built/sold, and it didn't turn out to be a problem, but DD does go on later into the night, so it has the potential to be more of a problem there.
My advice would be to buy where you really want to stay. When DH and I were buying, OKW and BWV were the only 2 properties available. We looked at both. OKW was a little cheaper overall, the room size was larger, we liked the laid-back feel, and we liked the fact that you could park outside your unit. We asked ourselves one question,"If we could never stay anywhere else again on WDW property other than here at OKW,could we be happy?" The answer was yes, so we bought.
We have been lucky because, in general, we have always been able to stay where we wanted, when we wanted, without a problem. We have been waitlisted a couple of times, and the waitlist came through. We are currently waitlisted for November to be at the BWV or BCV, but if it doesn't come through, we are back to our beloved OKW...not the worst thing in the world either!
Also try to think about long-term vacationing. Right now, if you have a young family, being close to the MK is great, because you can bop back and forth. Will you always want to have that ability? Or would you maybe prefer to have something more centrally located, when you are no longer vacationing with small children, but are vactioning with adults?
Each of the DVC properties has their pros/cons.
OKW has big rooms, a laid-back "beachy" feel, ability to park in front of your unit,nice main pool-but no slide or other fancy stuff like some of the other DVC resorts have, nice quiet pools which are consistent with other DVC resorts,rental of boats and bikes.
BWV/BCV have location, location,location!!!!!!!Rooms are smaller than OKW, but still amply-sized for a vacation condo. BCV has SAB, the best hotel pool on property.BWV has the Keister Coaster clown slide, which is good as well. Both also have quiet pools. They each have access to all the amenities of the Boardwalk, walk/boat to Epcot/MGM.
You know VWL, another beautiful resort, very serene and peaceful,cozy even. Access to MK,FW by boat, nice pool, love the geyser, love the Electric Water Pageant that you can see at night.
Good luck with your decision!