The Star Wars Adventure Journal was a publication by West End Games that featured supplementary material and short stories for their Star Wars Roleplaying Game, sometimes referred to as Star Wars d6.
Star Wars Missions are actually what I believe James was talking about -- they were sort of a mix of choose-your-own adventure books and baby tabletop adventures published for younger children through Scholastic. We're going to get our hands on one of them and play them in a future episode. I have foreseen it.
Brian was a kid I knew when I was 7 or 8 years old.
The Clone Wars: Legacy were a few story arcs of Clone Wars that were unproduced when the show ended. Some have been uploaded on YouTube with unfinished animatics, but full voice acting. If you can get past the dead-eyed, bug-eyed versions of the characters and the missing backgrounds, they're pretty fun. But they are not good things to show to children, no matter what Human Monster James D'Amato says. One arc was turned into the new canon novel Dark Disciple, and another was turned into the comic Darth Maul: Son of Dathomir.
Zonama Sekot is a living planet encountered by multiple Skywalkers in Legends stories. It can also jump through hyperspace, not unlike the Purgill.
The Father, Son and Daughter are three mysterious beings that Anakin and company encounter in the Clone Wars show that represent (we think) the Cosmic Force, the Dark Side, and the Light Side. We do our best to explain them, but it's all very wishy washy.