Final Fantasy I - Redux

You can assign properties, sprites and names to any character as long as the character has not permanently joined the party. If a character has permanently joined the party, then it becomes impossible to do so.

What does differ from a permanent joining and a temporary one ? I believe the only thing is a presence event bit that is set when the character join permanently so he appears on the airship or in the selection screen. Other than that it's the same command (3F) that is used to put a character in a party... Are you saying that the game nullify the graphics, palette and properties event command when a certain event bit is set for that character?

Edit: What if you remove the character from the party/crew (clearing his presence bit), change his properties and put him back in? Has anyone tried that?