Fakepilot,
1.Please see my short post above. The lift is caused by the forward motion of the wing through the air (the differential velocity). The forward motion is caused by the thrust of the engine, which does not need to equal or exceed the weight/mass of the a/c.
2. Helicopters have rotary wings. The lift is produced by the differential velocity of the blades (or wings) moving through the air. Directional thrust and speed is produced by tilting the blades.
3. Yes, but what about drag. Do you think that should be added to the weight? Concerning the second part of this question, I think that the answer is no, as there is no 'missing' force.
I hope that this helps.