when Lucasfilm gave the greenlight for the Expanded Universe Novels there were strict guidelines as to what could be written about in terms of timelines, ie: everything post Return of the Jedi was open game, whereas with the exception of Shadows of the Empire (BLECCH!) nothing was aloud to be written that might impact the storyline of the prequals or the original trilogy, I doubt Lucasfilm would allow so many books to be written about the characters post Jedi if he indeed intended to do a post ROTJ trilogy based on Leia and Han's children. I can't imagine for one minute that George would use anyone else's ideas as a basis a third trilogy, he'd have to start with a clean slate.