Let's break the question down into two parts, actually three:
NetBackup supports Exchange 2016. Assuming you have CU5 or later, you need NetBackup 8.1 for GRT support. EEB's are available for 7.7.3 and 8.0.
NetBackup with an Exchange policy doesn't care that the file system is REFS. If your chosen snapshot provider can snap it, NetBackup can back it up and restore it.
NetBackup with a VMware policy cannot protect Exchange on REFS. I don't know whether VMware support has been extended to REFS, but the Exchange ASC process assumes that it has not.