I' thinking that since I'm a sucker for the rule of 3 trope, that I'll have three arc for The Turtle Charm sequel:
As I posted before, the first will consist of Leo meeting Peter Parker, Zuko, and Mirabel Madrigal in the greater megaverse since they each have similar story beats to him.
Then in the second arc when Leo reunites with his family and friends in Tina's world, I'll focus a bit more on his romance with Tina and he'll meet her two most important ex's. I want to highlight how his relationship with her is different from them.
Then in the final arc, I want to do a "Turtles Forever" thing, bringing in the 2003 and 2012 brothers to play their personalities off of one another and the Rise boys as they face a previously established villain together.