Very discipline skiing! She is working hard on it! I would recommend making improvements in this order:
1. Even your daughter does not have pronounced aft stance, she would benefit from keeping her Center of Mass a bit more forward. She seems to be very comfortable with the slope and snow conditions, therefore I think her boots and possibly bindings affect her stance:
a. Remove additional spoilers (if they are there) from the back of her boots;
b. Remove “drivers” from the tongue of her boot(if they are there);
c. Make sure that her fore/aft weight distribution between toes and hills are 50/50 (not 75/25 as many boot shops love to set. Almost any boot shop can measure it, not every can set it correctly though)
d. Make sure that the ramp angle on her bindings does not raise her hill.
e. After you done with her boots and bindings and her balance still needs improvement (which I drought), have her ski in extreme forward position, then in extreme aft, then move from aft to forward within the same turn.
2. Your daughter is keeping her upper body square to her ski at all times, which quite possibly makes her throw her pelvis sideways to start the turn. Teach her lower/upper body separation, skiing in counter and into the counter. Start with 180 pivots drill
3. Your daughter would definitely benefit from a little bit more pronounced hip angulation. However, I suspect that as soon as you will take care of lower/upper body separation, angulation will fall in place by itself, since you daughter clearly demonstrate attempt to execute it correctly. Lack of lower/upper body separation does not let it happen to the full extend
4. Now, this is going to take some time. Your daughter puts a good portion of her weight on inside ski. This has been very confusing subject for the last few years, since we all have been taught to have active inside ski/knee. In the mind of majority (me including), more active means - weight bearing. This is not the case in here! This is not what PSIA meant! What they meant (took some bloody two years to discover) is that movement should be initiated by inside ski/knee (which totally makes sense), but at the same time PSIA have never implied that inside ski should be equally weighted with outside ski (transition between turns is the exception). Meanwhile many skiers became a victim of this strange wording and started to load their ski 50/50 at all stages of the turn instead of supporting majority of the weight with outside ski (nobody changed laws of physics with invention of shaped ski). Your daughter is one of them. When majority of the weight is not supported by outside ski through the turn (except of transition, where we want 50/50) following problems occur:
a. Travel of inside ski is shorter, so with equal pressure, inside ski should assume smaller edge angle then outside ski, which travels longer way. Here we have got unequal edges
b. If skier attempts to keep edge angles equal, that cause wash out of outside ski, because inside ski starts to make tighter radius turn then outside ski. Most of the time diverging tips follow.
5. It is not only sounds like; it is a can of worms! There are many, many post on this forum regarding this issue, make a search, pay attention to what Bud and Rick have to say. Meanwhile, as a good drill, have you daughter to make turns on outside ski only, keeping inside ski lifted from the snow and switching ski in transition
6. Once your daughter with master efficient weight distribution between skis through the turn, you will be working with her on more active inside knee, if that will not take care of itself on its own (very possible)