FYI, the WS-65819 is a 1080i set, does not accept 720p via component, and has a pretty good scaler for SD material. The latter being probably why your wife finds it acceptable to watch SD material via composite video.
Unfortunately, a separate amp is required to run zone 3. But since you have the BK, I’d run the 3 fronts & zone 3 off of it and power the surrounds & zone 2 with the Pioneer amps.