Most things will work well enough if you just have them as a stunt or merely an aspect, since "aspects are always true". As it is, the whole "free will vs. power" doesn't translate too well into the Accelerated mechanics, so it's going to be something you do on your own by invoking and compelling the aspects at hand.
Then there is the way you describe your approaches. A character with quick +3 and a matching stunt can almost certainly be counted as someone with a speed power. Once he increases in power, he can raise his quick approach, which will be kind of like buying a speed power.