GV on iPhone 4S with Sprint

I'm going to be leaving T-Mobile and head back to Sprint sometime in the next couple of months, and I'm considering dumping Android and going with the iPhone 4S. I recently made the switch to using GV as my primary number and I am curious as to how well this works on the iPhone now. Although I'll be on Sprint, I DO NOT plan on using that integration thing that Sprint offers with GV as I don't want my GV number to be tied to Sprint only. Not having much experience with the iPhone (used to own and iPad, but not an iPhone), I'm not sure how well integrated GV can be with iOS with Apples tight controls and such.

1. I know I can't really uninstall Apple's dialer, but can I at least delete it from the bar and put GV there instead?

2. If I use something like Yelp to find a business and I click the call button, does it launch the Apple dialer, or can I make it launch the GV dialer?

3. When I make a call through GV, does my GV number show up on the caller ID on the other end, or are they going to see my Spring assigned number?