Looks like you are on the right path. Do some CA exercises because your upper body is rotating into the turn.
I'd suggest more work on inside foot management. The sponge exercise you are doing is a good exercise for that and here's a detailed discussion with ideas for working with a sponge:
Feet together to learn tipping.
I'd also suggest having someone help you with the pole press drill (from Book 2) to learn how much muscular effort is needed to hold the free foot against the stance foot.
You might try lifting the tip first as discussed in this thread:
New stuff from PMTS, refined stuff from PMTS!Work towards mastering the Super Phantom with Touch-tilt exercise:
As in a regular super phantom, transfer balance to LTE of the uphill ski. Then, touch the inside edge of the lifted, downhill ski to the inside ankle rivet of the stance boot ("inside foot arch touches outside foot ankle"). Keep it touching while tipping the free foot further toward its LTE. Don't let that free ski touch the snow until the very end of the turn. VERY IMPORTANT STEP! At the end of the turn, when the free foot touches the snow on its LTE, immediately pick up the new free foot, and touch-tilt the new stance boot.
When learning, you can begin with keeping the tip of the free ski on the snow, but the goal is to keep the whole ski lifted throughout the turn which is a true test of your ability to balance on the outside ski.