Hi and welcome. The problem with alerting for zero byte incremental and differential backups is that they can be genuine case. Admitedly, also zero byte full backups can be genuine but are less likely to be. As for detecting if a folder/folder/DB is missing from a backup then you would need to develop your own custom application/utility/tool for yourself to post-process backup listings on the Master Server and yet also still somehow contact backup clients and walk their file-systems remotely and interact with thier DB products remotely to query lists of DB - to determine if anything was missed. The code would need to handle whether it was checking a full backup or an incremental backup or a differential backup, and so would need to handle dates and times - but your run/check/compare would need to start and complete before the next backup and before any users/database update any files otherwise the timings would all be thrown and you would end-up reporting false negatives.
Yes, you should be able to generate a custom backup report in NetBackup OpsCenter to list and report zero byte backups.