The bullet points are correct, except I would say that the PIAA deferred to the club-pro, not "sided" with them.
The coach of the player who had lost his ball conceded to the head pro that it was longer than 3 minutes that they looked. That point was never in dispute.
Don't know about any "committee".
Yes, intention to play 2 balls was announced.
If both players who signed the card were DQd, the remaining 4 players scores would be used to determine the team that won and it would have been the other team.
Ball 1....Tee Shot, Chip, 2-putt = 4
Ball 2....Penalty stroke for going back to tee...tee shot, chip, 2-putt = 5
This occurred on the 18th hole.
Hope that helps.....