2. I haven't had a change to try 3.6 out yet, does anyone know if the Mount feature is for the local storage snaps only or will it mount snaps from the SnapVault location as well?
Yes you can mount and umount snapshots on primary or secondary. For secondary you have to create a separate config and point SC at secondary volume. SC will clone a snapshot and either export it (NFS) or map igroups (LUN). After this you simply need to go into vCenter and do a rescan / import datastore.