Yeah you're definitely over-reaching that back foot. You want the shin of the front leg to be vertical. If you look at the videos you can see that your knee is in front of your ankle. So step out and make sure you're not reaching that back foot.
Also you want to make sure your back leg is not locked out. Try to keep your back knee soft so that if you were to absorb the weight, your back knee would bend and your hips would travel straight down.
Here's an example of Audra in the split: http://www.catalystathletics.com/med...p?photoID=2345
The slow dip isn't much of an issue as long as you're accelerating out of the bottom and that bar isn't moving while it's on the shoulders. I would suggest doing some Split Push Presses and work on keeping your weight distributed more evenly and keeping that back knee soft.