CURT Towed-Vehicle RV Harness #58902 with Brake Buddy?

Yes - they do interact because the brake lights turn on when the brake buddy applies the brakes.

The hopkins unit is the same as the curt

Well, I guess I learned something new. Did not know that. I thought the brake buddy simply got it's signal from a motion sensor that would signal the compressor to apply pedal. Is it a certain modal Brake buddy that does this? And, how does it get wired to sense when the brakes are being applied?
 
When you press your brakes your brake lights turn on even if ignition is off. That's how my tj is wired so assume others are the same. Brake buddy simply presses pedal. That would turn on your brake lights regardless.