Low brake pedal bad caliper?

Got a 2006 Camry with drums in the rear.

Adjusted drums, bled brakes and abs, lubed front guide pins that were stuck (made a good improvement but pedal still low).

I clamped the front hose brake lines and pedal was operating normally.

After that, pressed the brake pedal to build pressure and opened the bleeder valves on the front and they dripped.

This leads me to suspect bad calipers. I've never really heard of a caliper causing a low brake pedal so are there any other things to check for before ordering parts?

Visually, the caliper pistons don't really push out on their own (I can easily take them off and put them back on).