Obi-Wan Kenobi (Ewan McGreggor guest stars)
Darth Vader / Anakin Skywalker (Hayden Christiansen stars, or guest stars)
JarJar Binks (geeze we hope not - but maybe he could be tortured as a prisoner of war?)
Nute Gunray? (if he lives)
Watto (let's hope they don't go to Tatooine often or at all!)
C-3PO (Anthony Daniels would do this for sure)
R2-D2 (Kenny Baker might like more work)
Palpatine (Ian McDiarmid could guest star. Doubt he'd do a TV show)
Yoda (Frank Oz can send in voice tape-overs, but what if Yoda's on Dagobah?)
Captain Typho (if he lives)
Bail Organa - strong likelihood, as Jimmy Smits is know from television
Mon Mothma - established and with the Rebellion growing...
Grand Moff Tarkin
Boba Fett - 14 years old up to age 31
Aurra Sing (if she lives)
VARIOUS JEDI WHO HAVE STILL SURVIVED
Han Solo - 11 years old up to age 28
Luke Skywalker - 1 year old to age 17
Princess Leia - 1 year old to age 17
Lando Calrissian 13 years old up to age 30
General Madine (was an Imperial in those days)
There's a lot they could work with. However, the ultimate outcome of the story, like Episode 3, is known.
If the story did not focus on ANY of these characters, it'd be more believeable that one or more of them were in trouble, because they could then be able to DIE!
No matter what trouble Darth Vader, Boba Fett, or Han Solo get themselves into, you know that they live to enounter each other on Cloud City x-teen years later.