C.L.
Do the kids understand that all these characters shouldn't be seen together? If so, you've definitely got the makings of a spoof.
The Emporer interacts with Anakin and Darth Vader (playing up that they shouldn't be together... maybe telling Vader to go turn Anakin already or something)
Obi Wan interacts with Anakin and Luke... trying not to point out that they're related and will never actually meet (hi, I'm your son, but you won't know that until it's too late... sorry we won't get to go on any father-son fishing trips)... that sort of thing.
Definitely play up the fact that they shouldn't be together... and have humor for kids, but also for the parents!