1) There are two ways that N.E.X.U.S. can control the robots. The first is that they can all be coordinated together. It's as if all the machines, regardless of type, know what the next target is so they work in unison. The N.E.X.U.S. knows everything they know and can make better decisions. The second is when the N.E.X.U.S. can manifest itself in one of the true robots. It can't do this in one of the drones, only a true robot. It states in the first paragraph of that section that
drones contain some kind of organic components, while True Robots are machines made from metal and silicon.
For a better description of this, see page 36 the section of Possession by the machine.
2) I think it depends on the long range weapon. So it can't necessarily be always factored in. I'd add it to the normal bonuses.
3) This is GM's discretion in my opinion. Just make sure that it's consistent with the good guys as well as the bad guys. You could say that if you discover that you fail in the first attack, you can switch actions in the next. Or you could go the other way and say that anything attempted that fails is wasted.