Hello mate and welcome to the forum
1) Yes most certainly
2) Leakage no, low/no flow rate yes. MCubed T Balancer here
. Alternatively you can link the RPM cable from your pump to an Fan/LCD panel and it can give off an audible alarm if your pump stops.
3) Pump with res can give better pressure (top dependent) and can make your layout a little easier.
4) * Swiftech GTZ/D-TEK Fuzion V2/OCZ Hydroflow/XSPC Delta V3 (in no particular order)
* EK or XSPC GTX 260 blocks (XSPC are usually the cheaper option, but that's not a bad thing)
* Swiftech MCR320/ Thermochill PA120.3 rads. There are others about that aren't as efficient, and others that are more efficient but cost more. The choice comes down to you and your budget. Plus, the less depth/fins per inch your rad has means that it's going to have some decent fans to cool as efficiently.
* For the fans, Yate Loons (near silent) are extremely popular as are Sanyo Denki's, Noctua NF-P12, Scythe Ultra Kazes and Xinruillian's. There are quite a few other popular fans as well, but it all comes down to noise/performance ratio.
* As far as pumps go, the Laing DDC-Ultra would handle restrictive loops (like those with your NB and VRM blocks.