If that is an example of her swinging at an outside pitch she is way too far out front.
As far as flares (slices) and popups (if she is letting the ball get deep enough on an outside pitch) the problem is most likely having her bat head too low. One of the first things batters learn when we practice hitting outside pitches using front toss is that the bat head cannot be too low. To me the bat has the "feeling" of being more level than it should be when I first make the adjustment. Of course, it's not actually level.
There was a post on here some time back that suggested placing the pitching screen about 20-30 from the batter and offline towards 3rd base; then pitch the ball across the outside of the plate. For the first several buckets (about 75 balls) the batter will hit weak grounders to 2nd, slices, and popups. As they adjust the barrel angle they will start hitting right field gappers.
As a team drill this causes a lot of moaning and groaning. But it's very effective!