Diagnosing brakes: One caliper stuck, and no luck bleeding
 

I'm having two problems with my 2001 Boxster brakes:

1) .5 miles from home, the rear driver's side brake became stuck one night while driving. I made it home and smoke was coming from the pads.

2) After cleaning the rear driver's side brake caliper,* I began bleeding the brakes using a Motive pressure bleeder. I tried both rear passenger's side and rear driver's side, but with both of these, <20ml of fluid came out of the bleed nipples. I left the system attached and pressurized for 20mins and no additional liquid came out. This is unexpected

Any diagnostic advice much appreciated. Tomorrow I'll try a 2-person bleed to see if I'm able to get more fluid flow that way, and also try bleeding the front brakes.

*To diagnose 1, I disassembled, cleaned, and reassembled the caliper. There was no pitting, corrosion, or scoring on the pistons. All pistons came out by applying ~120PSI air pressure. There were no tears in the dust boots. I had planned to buy new pressure seals and dust boots, and probably still will, but I think the root cause may be an issue with the hydraulic connection because of (2).

There is a single hard line from the master cylinder area that feeds both rear calipers. It runs along the driver's side of the car near the pinch weld. I suggest examining it for possible damage.

Master cylinder failure. Clogged/debris in brake line. Damaged brake line.

ABS pump???

From the description of symptoms ...
 

... the most obvious cause is a clogged flexible brake line.
Believe it or not, flexible brake lines are wear items.
Happy Boxstering
Pedro