cPanel Incremental Backups

Im using cPanel tar backups, but I want to change to "incremental" because I think It will free proc/memory resources when Im doing a backup. I know that the space will be much more, but space is cheap. My question is, if the user delete one file when I do the next incremental backup it will delete the file in the backup? I want to have the backup not just for 1 day, I want to have 1 backup for day, one for week and one for month. I need to have 3 separate files per user file? Or the cPanel have the skill to store the bites changed? Like rsync/rdiff-backups?

How works the database backups? it copy the .sql each backup time and replace the old one?

Another question, exists a way to protect the disk that have the backup data for example if any one take root privileges and want to delete the data?

Thank you,