Yeah, theres not really a sort of list of what Lucas talked about regarding the prequels, you sort of have to read through the whole book. But really, there isn't a whole lot--it was all general statements. Theres a republic with Jedi, Kenobi discovers and trains Anakin, Palpatine was a senator and becomes the head of the Republic, a Clone war occurs, Palpatine lures Anakin to the darkside and betrays the Jedi who are somehow wiped out, Kenobi and Anakin fight on a volcano where Anakin gets burned up and becomes Vader, Kenobi works with Bail Organa to hide Anakin's wife and twin children, and somewhere in all of that there would be something called the Clone Wars.

Really, thats all we knew. The only additional specifics is in relation to the Clone War--not Mandolorians but "Imperial Shocktroopers." These were super-troopers of a distant origin, of which Boba Fett was a part of, who fought a war called the Clone War, which the Jedi were involved in, but were defeated by the Jedi.

But any of that was subject to change, as can be seen by the Clone War. The above "Shocktrooper" info was revealed in Bantha Tracks, and around the same time LFL also published that the stormtroopers were clones--so perhaps the Clone Wars were to be that the Imperial Shocktroopers tried to invade the Republic, the Republic created a clone army that was led by the Jedi, and when the war was over Palpatine used these as his stormtroopers. This was all invented around 1979 or so--before this Lucas hadn't developed the Clone War at all, other than it was a long-ago battle which the Jedi were involved in. In fact, one idea from 1977 stated that Lando was a clone survivor from the war, and came from a planet of clones.