No, it is supplementary material under the TPM 3D re-release, which makes it canon. Even Del-Rey novelisations are Canon when they directly reflect the films. Companions such as this, are supplementary to the movie itself. Pablo, who I am sure you are sourcing clarification from, was simply making a broad generalisation in reply to questions about Legends material.
Because it is a DK Publishing book, which have always been the publisher of G-canon source material for the movies. Movies are canon, the novelisations are psuedo-canon (where they aren't contradictory), the movie guides for them are considered as part of movie media.
I'd go on the circus of tweets that have been made about it, but I've never seen a quote stating movie media is Legends either.
Originally posted by AncientPower
If it is in reference to strictly Canon characters then the quote doesn't apply to Legends characters at all.
Originally posted by AncientPower
Not that a Level 4 Children's book should be relevant anyway.