I could have sworn I left a response to your post already. I've seen these videos before. Anyway, here's what I see:
Shot Preparation - The first and foremost thing you need to work on is your footwork and shot preparation. Sometimes you set up well, sometimes you don't. When you don't, often it's because you've stopped moving your feet and taking adjustment steps too soon, leaving you reaching or off balance. In addition, a wider, lower stance on both sides would help your set up and power. I know this was a casual hit, but, ideally, you should be loaded up (meaning wide, low stance with unit turn complete), ready to hit the ball before it gets there every time, if possible. If you're hitting on the run, that's something else. But, when you can, you should set up like this every time.
I like your groudies for the most part. You've got good upper body rotation most of the time. A wider, lower stance will help facilitate more consistent UBR.
BH - I like your backhand. The only thing I would suggest is that you keep your right arm straight in your windup. You don't have to lock out your elbow, although it's okay to do that. I didn't get enough of a look at it to say much more.
FH - The most important thing I can try to impress upon you is LOSE THE FLYING ELBOW. Keep your elbow IN and FORWARD, throughout your backswing and forward swing until contact. At contact is where your elbow should move up and initiate the WW finish.
Hope that helps.