Depends upon which books you’re talking about the Expanded Universe isn’t considered Star Was “canon” , but if Mr. Lucas himself released any kind of Episode Books for VII-IX then yeah, they’d be hard to reconcile those with these new movies.
There's actually quite a bit of dispute over that (see
en.wikipedia.org/wiki/Star_Wars_canon, which actually puts forward that there are four levels of canon and one of non-canon. Just another example of how nothing in the Star Wars universe (or, rather, "continuity") is ever simple and straightforward. Except that bit about Wookies pulling off peoples' arms when they lose ...