Hey there dopey. Let me be the first to welcome you here. Looks like we've got lurkers coming out of the woodwork on a weekly basis!
Your first question about the twirls... Yes, they are standard full finger twirls, but then again, they're not...

Most any kind of finger twirl move starts out with the basic twirl. But, instead of keeping the bali on the same plane (just going back and forth), I rotate it too, sometimes while twirling, sometimes while stopping mid twirl. It's basically like doing horizontal and vertical openings while it's between different fingers. The key is smoothing the transition between the twirls and spins so the bali never really has to stop (just ricochet now and again). Quite honestly, I couldn't begin to explain it and be understood, even by myself.

It's just a lot of experimenting, trial and error. Remember that MANY of the normal spin, rotate and richochet moves that you probably already know very well, can be done between any of the fingers.
Alright, the finger snap aerial... Just get the bali between thumb and index (like you're going to hit a button on top of a pole) so it's parallel to your body and the ground. Bite handle up, safe handle down. You should be able to see the grip quite clearly in the high quality version of the vid. Snap your fingers (pulling thumb back and pushing index forward at same speed) while moving up slightly and the inertia of the spinning bali will flip open the handles. When the handles slam together in the open position, you have a small window to slip your hand in and grab it. One more tip... it's extremely important to keep the knife straight and level before the toss, otherwise, there's really no telling what will happen.
Remember, just do what feels right. Everybody has their own minute little differences that allow them to do the move in their style. If you're accomplishing what you set out to do, you're doing it correctly, even if you didn't do it the way you learned. I'm sorry if any of what I said insulted your intelligence, or likewise went over your head. Not sure what level of flippin' your at. Anyhow, have a lot of fun, and stop by often!! Also let me know if you need more explination.