Okay, that clears things up. To answer your concern, you can still do animation cancelling while walking with Free Cast. Plus, animation cancelling doesn't matter for Sages anyways . . . unlike it would for DS dancing and the like.
Lastly, my memory on this one is fuzzy, but I do believe that casting non-instant spells automatically does anim cancel since the process of going back into mid-casting animation overrides the end of casting animation. Eitherway, it's still negligible for sages.