Set party lead character - Events

I did something similar to this in BNW (having all four characters spread out) and used some other event as a template, though for the life of me I can't remember which one. It might have been picking up Setzer's note in Owzer's house just before going to the Opera House.

For a single character acting away from the party, you could check the event where Shadow leaves the party after beating AtmaWeapon. The dialogue nearby should be something to the effect of "I sold my skills to the Empire" I believe.

Anyway, here's the logic behind how I did it:

Code:

Load caseword with characters in current party
Check for a certain character (let's call them Jimbo to avoid spoilers), as well as a certain key item
If both are present...
Call CA/C6AC (I don't remember why/if this was necessary; it probably saves the current party configuration)
Call CB/2E34 (this is necessary so the characters spread out and rejoin properly)
Set up the party with Jimbo and 3 empty slots (I'm pretty sure this has the dual effect of making them the lead, at least temporarily)
Move characters $32, $33, and $34 to where I want them (those correspond to the characters in slots 2, 3, and 4 in the party, making $31 the lead)
Perform whatever actions I wanted
Move characters $32, $33, and $34 back to the tile the lead character is standing on
Call CB/2E2B (so the player can't walk through impassable tiles, I'd imagine)
Call CA/CB95 (removes the other three characters from the map)

I can give you the raw bytes I used for the whole event as well if you need, though those shouldn't be too hard to find.

I'm not sure if this actually changes the lead character to Jimbo - I'd have to check my test save, but it's on my laptop which I don't have handy at the moment.