Yes, thanks for fixing the location of my post.
So – I did figure out that basically all of my lag was just due to my Sony Internet TV. Even when I used the RCA video output from the Pi to the TV, I saw about the same lag. (I also tried turning off things like “CineMotion”, noise reduction, etc., but it sounds like some digital TVs are just not meant for gaming.)
I rummaged up an old CRT TV, hooked up the RCA video and the audio, and the lag was gone! Plus now it REALLY has that retro feel, being on a tube TV…
Anyway, thanks for the support – maybe someone else can benefit from what I’ve learned.