Been awhile since I've commented, but I just had a thought. Couldn't Victini charge Jirachi to have the energy she needs to make really big wishes? Unless Jirachi requires a different type of energy, such as cosmic energy.
Viewing post in The Legendary Pokemon Breeder comments
She'd be granting her own wishes for everyone else, regardless of if they want them granted or not.
Like she'd wish that Lugia's ass would always be bouncing and then sprint off again, leaving Lugia complaining that she can hardly walk due to all that jiggle going on behind her.
I've got a good idea how to end the scene too, but that'll stay secret until it's written