Does DFSR replicate shadow copies?

No, DFS-R will not replicate the VSS shadow copies. Each server would maintain their own shadow copies. However, if you have bi-directional replication and you restore from a local shadow copy on server B, it would replicate that change to Server-A as long as that file doesn't already exist identically.

If the folder hash is different, meaning the file on Server A either doesn't exist, or is different, than a replication is initiated. If the file exists but is different, one version will "win" and the other will be moved to the DFSR Conflict and Deleted folder.

It's also important to note that simply copying a file out of a shadow copy will not preserve the Timestamp information on the file. This can cause major complications with DFS-R. Doing a "Restore" will preserve that information.

I don't have a good reference to point you at, but I am quite sure that DFS-R does not replicate shadow copies.

You could certainly setup VSS on all the replicas, and give them a similar schedules.

If you revert an earlier version of the file, that will change should certainly be valid and replicated out to all the members. The tricky point might be in the case of a conflict where you reverted the file at the same time updates were being made on the other replica.