Experimentation with brakes becomes as difficult as finding correct saddle for stoker!
Perhaps we are too old school but we rely on rim brakes only; D/A caliper front and Tektro-Mini rear. Sufficient for us; we do live in up/down hilly/mountain terrain and have never felt the need for a 3rd brake. We are a rather light duo (just under 250#) and have been riding on the roads TWOgether over 33 years and thousands of miles. This works great for us.
As for brake pad wear, seems many discs wear out pads at an alarming rate and brake needs adjusting/fiddling more often. When folks on a 'tana tour in Hawaii/Italy needed to adjust their Winzip disc several times on a long descent . . . I sort of scratch my head!
We've descended from 9200' elevation at 40/50 mph with rim brakes only and did just fine.
Have had one pair of Matthauser pads on Mafac rear cantilevers last 50,000 miles (gasp!).
However, your needs/expectations may be different than ours.
Good luck!
Pedal on!
Rudy and Kay/zonatandem