Overall, you look 100 times better than your first post!
Video #1, Trotting:
Remember to keep your shoulders rolled back and elbows at your sides - you tend to keep your arms a little too straight. You want almost a 90 degree angle in your elbows.
Keep your legs underneath of your hip.
You still have that nice tempo!
Video #2, Cantering:
The first half of the video started out really well! I'm impressed with the change! You sat deep and your hands didn't bounce - I would say that's because you sunk down into your heels more and let your legs absorb the shock, and sank down on your hips so you weren't bouncing out of the saddle. At about the midway point on the video something happened and you started bouncing again - make sure you keep sinking down. Another trick you can try is thinking about shining the saddle with your bum - it sounds silly, but rock your hips in the saddle so you're buffing the saddle from back to front through the 1,2,3 beat, then on beat #4 (when the horse's legs are in the air) reset yourself back to the back of the saddle.
Overall there is a HUGE improvement. Remember to keep your arms bent at the elbow.
Video #3, cantering:
Very nice with your shoulders at the trot at the very beginning! And then... what happened? You went back to bouncing and your hands were bouncing as well! Your seat was bouncing out of the saddle. My advice here is for you to drop back down to a trot and start over, and sit deep into your seat from stride #1 - it's easier to do that than try and regain your seat after you've started bouncing out of it.
All in all, your riding has really improved, and if you keep improving at the rate that you seem to be ... look out world!!