I'm not sure what the details were behind Jabba (human or just a human stand in for stop motion added in later), but Boba Fett was definitely NOT supposed to be in there. The reason his figure came out pre-ESB is, like Ric says, because he was in the Holiday Special on TV. He was one of the featured characters. Don't worry, this confused me too because I had no idea that a TV HS existed until a year ago. It does explain a lot though.