However, there seems to be a new protection method against flashing combination / factory devices on these phones. I attached a screenshot of the error in Odin. The screenshot text is not very clear but the message is "Please get the approval to use factory binaries (BOOTLOADER)"
(But however if you remove the sboot.bin the other partitions will also fail anyway )
I am working on modifying the CSC and regions to enable certain features for custom roms but I must first bypass this issue, if even possible. If anyone has any ideas I don't mind risking bricking the device to test something out.