There are some projects I saw where people made some mods, etc to make thoes things possible. You have the capability to change anything you really want but it requires a lot of knowledge with what you are doing. HARD BRICKING isn't the problem but the problem is to unlock the PBL which probably needs a token from SBL that will let you get premissions to unlock the PBL. I still don't know why you have OEM unlocking in options, it could be a OS thing.
Go look on the forums, there is a samsung service thing ( I forgot how its called, you will find it somewhere) that will let you unlocking the PBL but not for A12. If you know what you are doing you can take the source and modify it for you self.