If We Go Back to Gongaga in Part 3

I can think of two reasons to go back there.

1. To inform Zack's parents about his fate. Rebirth never lets us when we go back there to do sidequests.
2. Cissnei could be in danger of getting killed by whatever Shinra sends. Despite what Cissnei claimed about covering up in the protorelic sidequest, Scarlet could've been smart enough to realize that Cloud's party passed through the village to get to the abandoned reactor. So killing CIssnei might be a method to remind the villagers, coalition, and the rest of the Turks who's boss.