As for getting a fighter cast spells, I don't know. Armour will interfere. You might be able to make them into innate abilities instead, but I'm not sure how to do that. The quick casting thing comes from 9th level spell Improved Alacrity. I'm not sure how the game deals with it, but the most obvious option would be flags. Get a mage, cast it, save, and see if anything changes in the flag window.
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