Other mistake: During the Battle of Teth (the pillared jungle planet), the AT-TE's shoot the ledge at the top and there's not a single mark on the ledge afterwards, despite being hit with several joules worth of fire.
Other mistake: During the Battle of Teth, a walker fires at one of the pillars. In the next shot, it hits the very top ledge. Problem is it was actually aiming at the middle, as was the other walker.
Answer: Canon in the Star Wars universe is a somewhat complex term as it has several levels ordered in a hierarchy of precedence. Facts stated at a certain level are considered as canon, unless contradicted by something at a higher level of canonicity. The uppermost level of canonicity are the six live-action films. Lucas has stated that the television episodes (which include the Clone Wars movie, which can be considered as the first episodes of the TV series) are to be considered as the next level down in canonicity, so below the films, but above any other releases (books, comics and so forth). So, basically, yes, they're to be considered canon, except in any case where they contradict something established in the live-action films.
Tailkinker ★