Okay, I think I got it figured out: see, the Sarlacc pit wasn't any ORDINARY pit...it was a wormhole to other dimensions. And Jabba the Hutt didn't die when Princess Leia choked him with her chains - he just PRETENDED to die so that she would stop choking him, at which point he snuck away and went to hide IN the Sarlaac Pit as his pleasure barge exploded, only to discover he was being transported to DIFFERENT DIMENSIONS!
And when he got to each new universe, he enslaved some girl he captured in the exact same manner as he did with Princess Leia, because that's just his thing. Oh, also Boba Fett was hanging out with him, because, ya know, why not?
There. Whew. This is all fits into a single canon now.
1. Harley Quinn
2. Princess Peach
3. Wonder Woman
5. Princess Zelda
7. Asajj Ventress (Jabba, uh, briefly went back to his normal universe? Also he went back in time. Yep, this still fits)
10. Captain Jack Sparrow (it was here Jabba finally found true love, and thus never needed to put another Slave Leia outfit on a character from another universe ever again. The end...or is it?)