Diver 1's turn pressure would be 1700 psi on stage and doubles.

Diver 2's turn pressure would be 2400 psi on doubles.

Both would use 72 cf for penetration and another 72 cf for exit. This would leave Diver 1 with 72 cf for an emergency and Diver 2 with 94 cf (roughly).

In theory only, it appears Diver 1 could get both out of the cave alive even if Diver 1 dropped his stage early and then Diver 2 had a catastrophic gas loss at max penetration. In reality, however, 1 or both divers would most likely die.

Here's why - Diver 1 has 144 cf available in his doubles. If he uses 1/3 for penetration (after dropping stage), then that leaves only 96 cf in backgas. Diver 1 needs another 48 cf to get back to his stage. That leaves 48 cf for Diver 2. That last 48 cf is sufficient to get Diver 2 back to Diver 1's stage. But then Diver 1's doubles are completely empty. And all they have is a stage bottle with 48 cf left (which is enough to get them both out, theoretically). BUT UNLESS they were both VERY good at traditional buddy breathing, you'd have 2 divers fighting over one stage bottle. And you'd have 1 if not 2 fatalities. So many other variables not taken into account here (exit flow, stressed SAC rates, faster exit swimming rates, fumbling at stage pickup).

Best option would be to carry the stage the entire dive. Ditch the stage on exit when it goes empty, and run slick for the door sharing 7 ft hose.