Chee saying "everything owned by Lucas is canon" doesn't apply to novel blurbs. Blurbs, cover art, the paperback itself etc, are owned by the publisher.
In this case the publisher of most Star Wars books, Del Rey, isn't owned by Lucasfilms/Disney. Their parent company is Random House Books, who also happen to publish George R. R. Martin's books, along with countless others.
__________________ “The galaxy must experience the pain of death and the rapture of rebirth as I have. I will bring chaos. It is time for war.”
They don't own creative/copyright rights, though. Unless I'm mistaken, it would be a breach of contract for Del Rey to go outside of Disney/Lucasfilms and get someone who isn't Drew to write some Darth Zannah books. You need permission from Star Wars to write Star Wars books.
Point being, nobody from Lucasfilms is responsible for, or has any authority over, what goes on a blurb.
__________________ “The galaxy must experience the pain of death and the rapture of rebirth as I have. I will bring chaos. It is time for war.”
Yeah, so for example, a single author could go to a publisher and try to get their work published. In the contract, they would cover film and translation rights. The publisher would say something like "we'll pay this and this if you let us translate your book to Russian, and this if you give us the right to make a movie out of it."
But, clearly, Del Rey doesn't have film rights for Star Wars. On the same note, they clearly don't have control over what goes into the book itself, aside from saying "We'll publish you, but only if you change this" - it's still up to the author whether or not they make the suggested changes.
The publisher only draws up a contract with the author, gets their permission for X, Y and Z, and then sell the book. The key word being sell.
__________________ “The galaxy must experience the pain of death and the rapture of rebirth as I have. I will bring chaos. It is time for war.”
My argument stopped hinging on fallibility a long time ago.
Is it a point in favour? I guess. Is it something I would rely on if there was nothing else? Not a chance in hell. I don't disagree with the blurb but that doesn't mean it's coming from a reliable/official source. A layperson can be right about something but that doesn't mean they have more authority than an expert in the field, or in this case, someone who has the right to sell and advertise does not have creative rights for all of Star Wars.
__________________ “The galaxy must experience the pain of death and the rapture of rebirth as I have. I will bring chaos. It is time for war.”
No, a breach of contract would be for Del Rey to publish a SW book outside of the LucasBooks imprint, the Lucas company and publishing arm of Lucasfilm that publishers like Dey Rey (and DK, and Titan etc.) have the rights to create SW liscensed out to. Much in the same way that independent authors like Drew, who are not Lucas companies, and whom often write content for other universes, like Mass Effect, are liscensed as authors by LucasBooks.
Or in other words yes, the blurb is produced by Lucasfilm, or rather Lucasbooks, a Lucas company, just through a series of third parties. And yes, all of it is ultimately owned by them. Case in point, on the back cover of the Darth Plagueis novel, right beneath the blurb, is the following: