Is there a way to manage replication policies from legacy disaster recovery module (dfdrm.exe) with APIs/SDK?
The dfdrm doesnt have API/SDK, instead only cli. BTW why do you wan to use it and not Protection Manager ?
Customer is heavily using vFilers and DR vFilers, and to my knowledge, PM has numerous limitations in that context.
Thats true, OCUM doesnt support vFiler DR and support vFiler only via vFiler0 or physical filer.
Why dont you try this NMC plugin for vFiler DR.