Preface - I'm just going from what I think it would feel like to be in these positions. I never had instructor training, nor am I "up to date" so to speak with the instructor technique du jour, so take what I say with a grain of salt...
Some pressure on the inside ski is ok and I think it's currently considered good technique because you are able to initiate the next turn better that way, without lots of upper body rolling and such. But I still think your feet look a little too close together. If you think of an athletic stance more like "shoulder's width", like a little wider than just standing at "hip width" with is what it looks like your doing. The wider stance will give you more stability, but it means that as you add pressure to your inside ski, the forces can get out of alignment from the the downhill ski making your skis want to track differently. That's where I think you get the idea that all weight should be on the downhill, which works fine but requires more adjustments as you transition from ski to ski and will slow you down if you are trying to get through gates quickly.
Now on to the "posture". I think you are dropping your arms. I think it's because of your pole plants. When you ski moguls, or have to hop-turn in a tight chute, go ahead and pole plant like you appear to be doing. But when your cruising on a carved turn, the poles should be out in front, and use them more like a tightrope walker would use a long pole - horizontally - to counterbalance your upper body. If you tilt the pole horizontally a little, you'll feel the counterweight effect, which give you the ability to make small corrections to your lean angle if you need it, without doing a lot of bad things from your lower back area that will leave you feeling sore the next day.
Otherwise, I like your lower leg position - forward flex, bent knee, skis sliding independently. Since you don't give a pic of your turn initiation, it's hard to say about weight being too much back. Remember that stance is dynamic, and you should look differently when you are getting ready to carve from when you exit the turn, and in traverse (anticipating next move, but not yet initiating).
Now let's see how my critique holds up with the pro-instructors here.