It sounds like you already have a pretty well-thought-out fanfic here, with a wide range of diverse characters.
I didn't quote all of it because it's pretty long, so I'm only focusing on a few points here. Since you put in such an effort to share with us, I'd like to talk about a few of your plot points rather than posting anything of my own, if that's alright.
Spectral Steel did say we're allowed to post info on our original characters AND discuss them, so...here goes. (Yes, I talk a lot, sorries.)
First off, it's interesting that you made the Evil One the Princess' father. (A lot to live up to, that.
) This caught me right away because it seems I'm not the only person to have thought of it before.
I think what got me started on that was the timeline posted on Rainbowbrite.net. At one point, it says: "The Witch and Wizard are banished to Prison Planet." Not having watched Star Stealer for several years, I somehow got the impression that Prison Planet was the name of the Princess' abode rather than the remote location to which Rainbow Brite and Krys were sent. I had also forgotten about the two old people who watch Rainbow and Krys fly away. ("I remember when we tried to run away." "I can't remember that far back.") Even had I remembered them, the fact that they were a witch and wizard escaped my notice. Since the summary of the Evil One made him seem like a wizard figure, and occasionally referred to him as the Dark One (similar to Dark Princess), I assumed that the "wizard" mentioned in the timeline was the Evil One, the "witch" another villain whom I didn't recall and who got together with the Evil One during their stay at Prison Planet. Oy. >.< How's that for crazy interpretations?
But come to think of it, if Prison Planet has existed for such a long time, then someone of the Princess' lineage must've put them there before she herself was around--the gal's not that old!
In your paragraph about the evils, you say that the Evil One wants a son. So here's a question: is the Evil One still alive in your story during the events of Star Stealer? I mean, he must be, but where is he kicking it while all this is going on, and what's he doing while people are fighting over the preservation of the universe? The Princess kind of made a name for herself; you'd think he would have noticed something, right? And seeing as she almost succeeded in blowing up the universe, she apparently has skills which would be to his liking. Stubborn he may be to have a son, but what does he think of his daughter after witnessing her destructive talents? Just curious to see if you have any thoughts on this, because if the Evil One is indeed alive, then there must be a very legitimate reason for his uninvolvement in all these important events. Keep up the good work.