You can't pass under pace car at all, so JPM couldn't get back on the lead lap nor could he have let anyone past him. As soon as the lead car is behind the pace car the entire field has to form into a formation line and hold position until the pace car pits in and the leading car crosses the start/finish line. There was nothing to gain, only everything to lose.
I didn't hear anything about Montoya being fined, I did hear that he sounded almost apologetic on the radio to his team. I wonder what we all don't know?
As for Sato, I don't believe that for a second. Firstly, Button isn't their technical director, so I doubt he'd honestly be in the know on such matters. Secondly, it just seems incredulous every spectator in the stands and person watching on TV could expect his engine was going to go shortly and the team didn't.
I believe BAR were making the best of a bad situation. I don't know if they knew Sato's engine was bad before the race, but it certainly was from the moment the lights didn't go out and he leapt off. If you're a real consipiracy theorist you'd say they told him to jump start and get ahead of Michael, knowing he'd hold him up long enough to make an impact on the race but yet be out before the stewards would investigate properly and give him a penalty. As it is I think they at least used team tactics to baulk him. Sure, Ferrari's done that a million times, so credit to BAR for giving them a taste of their own tactics, but if that's truly the case, the manner in which it was done could have been a lot more professional.