Is everything in Dragon canon?

[Jhulae]

If by 'canon' you mean Official, then yes, Dragon is 100% Official material.

However, just because it's Official doesn't mean it's not optional, just like stuff from the many accessory books.

 

[Dross]

I've dropped the issue after he made his decision. I don't mind asking for/about things, but I don't like pressing the issue.

It just seemed odd the way he came out with it; at first Dragon is optional, then its canon--my term, not the DM's--for his game. I guess I should have asked him about the Incubus last month! Darn those WotC guys!

While the DM is free to say what goes in his campaign, he does need to be consistent (which going by your orginal post he wasn't).

You could go back and ask about the different calls, he may just have some specific reason for not allowing it (does not fit the theme maybe).