1. As long as pump is primed w/ water it doesn't matter what direction it is in.
2. Doesn't matter what direction the radiator is. The only benefit of having them at the top is that it will be slightly easier to bleed.
3. A 2x120mm radiator will be sufficient depending on your fan choice. If you plan on using some low speed fans don't expect to get stellar temperatures.
BTW there is nothing wrong w/ Swiftech radiators in terms of performance. If it funny how many times this graph needs to be posted.