Hi Steve.
Restoring on remote server is completely supported. further more. snapmanager has built in mechanism to test the restore on the remote server after each backup (it's get mounted on temp mount point and loaded to SQL).
it's seems to support iSCSI/FC LUNS, SMB Shares and VMDK. however i don't see if RDM is supported (i believe it is). needs to check it against the specific version and ontap mode documentation.
https://mysupport.netapp.com/documentation/docweb/index.html?productID=62300&language=en-US
https://www.netapp.com/us/media/tr-4369.pdf - SMSQL 7.2 Cdot best practices
https://www.netapp.com/us/media/tr-4232.pdf - SMSQL 7.0 7-mode best practices
i believe that's kind of answer your two first questions. not sure what the answer for the others
Gidi