I do...
If you aren't going to attack physically, I wouldn't have the dash...
I mean, if you did, there would be a dash forward, a fadeout, then a fadein where the person would just stand still, away from the enemy anyway, and cast a spell...
I would suggest just switching out the animation at that point, so that the spell character would simply replace the idle character, giving it the appearance of having simply started the spell where they stood...
Alternatively, you can have then take 1 step forward like they do in FF6 to cast their spell, but still, no dash effect (that is, don't have a frame without a character graphic in it)
Hrm... Did I make that too complicated? Because I feel like I talked in circles for hours... But, do you see what I meant?