getFolderFiles should merge the information for all snapshots to produce a unified "newest files" result
The current implementation chooses gets an arbitrary single participant from the folder and presents its snapshots as canonical. If a folder has more than one participant, one might not be all the way caught up on some or all files so picking it will give a stale view of the world.
For starters, don't worry about conflicts. Just presented a merged view of the consistent case.