THE SOLUTION IS HERE FOLKS
Apparently I was drastically overthinking it. Modifying the main lobby events file to trigger the event offline? Digging through the save file to see where the character unlock flag is? All meaningless. All you need is a save file from someone who has the Supreme Kai of Time unlocked then you copy one of their entire character data blocks and then calculate where your next potential character data block would be after the last character in your save file then import their character into that empty slot. Then you boot up your game and select any of your own characters (not the imported one as for some reason they will start at the beginning with a glitch from importing manually with a few errors) and the Supreme Kai of Time unlock will be automatically copied to all character data blocks and you can then let the game autosave and quit back to the character menu and delete the imported character. I wouldn't have guessed right away the contradiction that even though it's a universal unlock between all the characters in the save file that it would end up just relying on the world tournament completion progress from any of the character data blocks showing it was completed once from any of the characters and unlocked in all the character blocks automatically. Full details on how to do this yourself are in the save editing thread.
Apparently I was drastically overthinking it. Modifying the main lobby events file to trigger the event offline? Digging through the save file to see where the character unlock flag is? All meaningless. All you need is a save file from someone who has the Supreme Kai of Time unlocked then you copy one of their entire character data blocks and then calculate where your next potential character data block would be after the last character in your save file then import their character into that empty slot. Then you boot up your game and select any of your own characters (not the imported one as for some reason they will start at the beginning with a glitch from importing manually with a few errors) and the Supreme Kai of Time unlock will be automatically copied to all character data blocks and you can then let the game autosave and quit back to the character menu and delete the imported character. I wouldn't have guessed right away the contradiction that even though it's a universal unlock between all the characters in the save file that it would end up just relying on the world tournament completion progress from any of the character data blocks showing it was completed once from any of the characters and unlocked in all the character blocks automatically. Full details on how to do this yourself are in the save editing thread.