VFILERS parameter is depricated you never need to set it anymore.
From SC there is no difference between phy filer and vfiler and you configure vfiler just like normal filer. If your vfiler is vfiler1, volume is vol1, and dataset snapcreator_vfiler then you would have following:
Make sure vfiler name in DFM and SC match, no ip addresses
There is a video on how to setup PM w/SC so check that out under videos section in SC communities
We use DFM for protection manager integration. In this case it's suggested/correct to use the DFM as proxy instead of going directly to the storage for the operation? What's the real difference between using/not using dfm proxy?
The difference is do you want SC to send APIs to storage system directly or go through DFM server that is what proxy does, allows SC to not communicate w/storage system directly and you can manage rbac through DFM.