My first attempt at MA. Be that as it may, I will have a go at this.
I want to focus on the first two segments because those are the turns that did not work and it was not because the terrain was wrong.
I am seeing a weight transfer to the LTE before the completion of the turn. The old stance foot thus becomes light and tends to wash out a little which occasionally shows as an abstem. This motion robs the old stance ski of its energy and motion and you are completing your turn on your inside LTE and then moving into the transition. This essentially makes the turn into a two footed release without the second foot. This might be ok, but your new stance foot which is still on LTE does not flex which results in an unweighting of your new stance foot as your body moves up and over your stiff leg. As a result of the unweighting, your new stance ski is light on the snow in high C and your body is moving into the inside of the new turn before the ski has good contact with the snow which causes it to skid. Your new free foot does tip nicely, however it has started late because your old stance foot was not actively lifting and tipping. The result of all this is an abrupt edge hit when your stance ski finally has enough weight and angle to lock in. At this point your free ski is often light, but the force of the abrupt hit forces your free foot to take weight and the cycle begins again.
I see two things to work on here. 1) Phantom move and 2) Flexion.
My spidey senses tell me you probably have a hard time balancing on your stance foot all the way through your turn. I can see this reflected in your need to go straight and gain a little speed as you begin the second video segment, and also by noticing that your free foot ski only comes off the snow occasionally just before the fall line.
1) I would recommend practicing a slow motion exercise: Start from a stand still with skis perpendicular to the fall line and lift, tip and pull back the downhill ski while releasing from the uphill LTE into a brushed turn. You can start with garlands and then move to a full fall line turn if you want. Essentially this is the exercises from Expert Skier 1, 4.4 Full Release on Blue Terrain through 6.6 Two Footed Immediate Release. Javelin turns with the LTE ski off the snow all the time except in transition would be the goal when moving from this slow motion exercise to higher speeds.
You are using your inclination to the inside of the low C part of your turn to get your weight on your new LTE because that is the only way to get your weight there without flexing your stance leg to release into the transition. The end result of this is that your skis have lost their energy and your hips are slow to move to the inside of your new turn. You then have to wait until your new stance ski has reengaged after your weight has come back to it in late high C to begin to get higher edge angles.
2) Standing still, lift your uphill foot to mimic the free foot lifting and tipping through the turn. From this position flex your downhill stance foot leg to bring your free foot LTE in contact with the snow. Do this a few times and then tack it on to the slow motion exercise in 1). Do this in slow motion linked brushed turns on a green slope. After 1000 of them add some speed and see what happens.
This brings us back to point 1). When you flex to release your stance leg, and continue to lift and tip it, your hips begin to can move across your skis to the inside of the new turn during the transition instead of having to wait until your stance foot ski is reengaged at middle high C, and your new stance foot ski BTE can begin engagement with the snow immediately. One really important point here is that it is really hard to flex your stance foot leg if it does not already have some extension. Sometimes you get caught with a lot of flexion at the middle and end of the turn. At this point it is hard to flex more to release.
Here is a clip (00:00:13) showing your ski tracks in the previous turn. See how there is a skid at high C and the ski has not engaged until the fall line.
Here is the abstem/washout resulting from an early transfer to LTE without a flex to release on the stance foot. (00:00:56)
Here is a comparison of stance leg flexion at apex 00:01:31
and transition 00:01:32