Hi Andrew - I am Rick Vanover and I work for Veeam. Yes, if the Veeam Backup & Replication Server has a NIC directly on the iSCSI network, and the iSCSI initiator configured, the direct SAN access should work as expected to perform backups.
You can poke around the Veeam Forums and you may be able to see others with similar configuration, but I don't expect an issue with what you've identified above.