As far as Final Frontier, there was just too much in that movie that I couldn't accept for me to accept it as canon - Spock's half brother whose mother is a "vulcan princess" - I don't remember anywhere else anybody talking about vulcan royalty,
Though there is a lot about Vulcan they don't talk about. like the fact that they generally kept the whole they get horny every 7 years and will totally murder you if it isn't dealt with thing under raps.
the fact that it takes only six hours to get to the center of the galaxy,
I believe someone once noticed that the TOS Enterprise could have completed Voyager's 70 year trip home in about a month or maybe less based on TOS speeds.
the fact that the center of the galaxy is not a black hole (which is the prevailing scientific theory, and was I believe even at the time of the making of the movie),
Meh, Star Trek pretty much ignores science if its in the service of the story.
the fact that the Enterprise fires photon torpedoes and they explode only A FEW FEET AWAY from kirk, Spock and McCoy.
Then Enterprise came out and mentioned their predecessor weapon's yield could be adjusted to take a spec out on a shuttle without scratching the shuttle, so not that far fetched.