Kyle;

Shop air at around 100PSI (OK maybe 150PSI unregulated) doesn't nearly make the pressure necessary to budge caliper pistons which haven't moved in years and which may be corroded in place also. I suggest you plumb them up to a vehicle and use the significantly higher pressure available in the brake system to motivate pistons (use limiting blocks to prevent first piston which moves from popping out...hydraulic pressure is done after that!) Bleeders were likely scavenged so obviously would need to be replaced first.

You can make the call about just getting reman caliper after they are apart and you can inspect what you have...for $40, with exchange, I'd consider it...that's quite reasonable! I have no experience with these, but it would be worth it just to avoid the pain of extricating the pistons in yours just to find that they were totally corroded and needed replacement anyway...

I prefer premade lengths of brakelines...no muss, no fuss (British threads, NOT US!)

Good Hunting