CP for pokemon are pretty much completely random, however the higher you level up the more you'll encounter wild pokemon with higher CP.
For the most part, the same pokemon with have the same multiple when they're evolved. Though the pokemon's weight and trainer level might be a factor according to the pokemon go reddit page. Pokemon that have their radial gauges, when your own their stat page, closer to the right side are stronger.
This depends. Sometimes you're able to catch pokemon with higher CP faster than it take to feed them candies to up their CP. Before evolving you want they as maxed as possible, because when you evolve the game applies a set multiplier to your existing CP to get your new CP for your evolved pokemon. However, you can quickly level up by catching a bunch on pidgeys or rattatas and evolving them without much consideration while you have a lucky egg active.
What I do is, focus on catching a bunch of the pokemon I'm wanting to evolve. I put a star marker on the highest CP pokemon of that catching batch, transfer most or the rest of the bunch for candies, and power up the one highest pokemon I caught. That's how I got my 539 CP Eevee, and when I evolve him it should be well over 1k CP.
Also check out this CP spreadsheet to get a rough estimate of the evolved CP level.
@TACOBERTO - LMAO! yes! it's pretty funny how easy it is to spot other players XD I hear Chicago has a lot of great Pokemon locations with lots of pokestops and gyms. LUCKY!
I think it's definitely a great game. XD Though yes, the servers can be SUPER annoying and buggy at times, however, I haven't seen anyone giveup on the game because of it. I'm happy that it's motivating me to walk and relive that excitement I had when first playing Pokemon Red and Blue ♥