BUT the overal event or elements of it probably are.
Well lets see... The vong war takes place 25-29 ABY, and Episode 7 takes place around 30 years after Endor. We know enough about Eps 7 to assume the vong aren't part of it. We know Chewie is a alive as well. So best possible case, or worse depending on your pov, is the vong could be mentioned in passing. But given what we know about Eps 7 it seems more likely they're simply non-canon now.
If episode 7 doesn't mention them, or show any effects of them. Then those books are no longer canon in any way. Same for every clone and rebirth of Sidious that isn't mentioned, if he isn't the bad guy, and there's nothing mentioned about him. Or even more conclusively it's stated that the Battle of Endor was the end of him. All those books that featured him are no longer canon.
There's no way to handwave away the main bad guy actually being and staying dead.
Some characters may be be exceptions... Say for example Thrawn, even if he's not mentioned directly you could maybe make an argument he's still there somewhere. But for something like the Vong Invasion, if that's not directly mentioned someway, then it didn't happen, because that had too much of impact to leave no trace.
Edited by VanorDM