(0). Ouch, our spreadsheet is ugly.
1. Collisions: I don't really know any hard numbers
2. Fuel savings The largest part of the fuel saving is about using ion engines instead of hydrogen. The hoisting mechanics are interesting though. Equations coming soon.
3. Oscillations: Dampening is trivial, I am not concerned.
4. Maybe, at least partially. Again depends on the equations from 2.