Is there a way to force a complete replication of all files including unchanged files?
No. If DFS Replication considers the files identical, it will not replicate them. If changed files have not been replicated, DFS Replication will automatically replicate them when configured to do so. To overwrite the configured schedule, use the WMI method ForceReplicate(). However, this is only a schedule override, and it does not force replication of unchanged or identical files.