Both my rads are in a pull configuration, not for any performance reason, but just easier to clean that way and its how the internal rad mounts to the case. I could go push/pull for extra performance, but I'v got 2x360mm for just my CPU at this point, I think Iv got enough radiator performance :lol:. And fans are expensive in these kinds of numbers.
I have the XSPC X20 750L V2, which is a combination reservoir and pump.
Though if you are making a fully custom loop (not a kit like I did), I advise getting a dedicated pump and reservoir. Iv found that having a pump/res makes bleeding and filling somewhat difficult. Also having it mounted in the 5.25" bays makes it fairly loud since you cant really pad it to reduce vibrations.
Would depend on the particular radiator, fans and whether you are running in push/pull.
At a rough guess, maybe. A single 360mm could hold it, but you would be at the threshold I think.
Have a read through the water-cooling sticky, it will give you all the info you need and links to resources where you can find more specific information. It even has a section dedicated to figuring out whether you have enough radiator (TDP section).
http://www.tomshardware.com/forum/277130-29-read-first-watercooling-sticky
Might take two or three reads to fully understand, but it covers pretty much everything.