Question 1: Yes, you should be able to reach 60FPS as most places.
Question 2: The resolution has nothing to do with the real size of the screen, depending on your eyes, you might even use a lower resolution since 1920x1080 is going to be *really* small on 15 inches.
Question 3: Personally, for best performance/price take the i5. The i7 would kinda' be a "waste" when looking at the rest of the system. You wont see *that* much gain over the i5 since it depends on the rest of the components too.
I hope that helped you a bit, I can of course have made a mistake and I think others should give their opinion too ^^
Good Luck on your purchase
