Question: Who is the pipe smoking man in the black and white photo taped to Nedry's computer monitor? Some computing pioneer?
Answer: Dr. J. Robert Oppenheimer. One of the fathers of the atomic bomb. I don't know why Nedry would have his picture up and you can draw your own conclusion, but it does seem to be a reference to how good science can lead to destruction.
Answer: He also said, "Now I am become Death, the destroyer of worlds."
Question: Considering at least the T-Rex, Raptor and Dilophosaurus fences have been destroyed / damaged, wouldn't turning the power back on just cause the circuit breakers in the maintenance shed to trip again?
Answer: The breakers tripped because of Mr. Arnold resetting everything, not because of the fences being destroyed. So they had to try to turn the breakers back on to get any power to anything on the island. Ellie was following Hammond's direction, so she didn't have time (and didn't really know which ones) to think about which fences were and weren't destroyed. At worst, if some of the fences were down, those specific ones just wouldn't have a current running through them.
Question: When John and Nedry are arguing in the control room, John tells Nedry "I don't blame people for their mistakes" - What was the mistake that Nedry made?
Answer: Hammond's comment is a reference to what Nedry said about the amount he bid for the project. It's implied that Nedry has financial problems, and Hammond is basically saying that those problems are not his concern.
Answer: There wasn't one specific thing. Hammond was complaining about the number of computer glitches that were occurring while Grant, Ellie, and the others were on the car tour and also about Nedry's generally sloppy work. Nedry tries to blow off Hammond's concerns and makes excuses, falsely claiming the poor work quality is because he was the lowest bidder for the job.
Question: After John asks Muldoon to take one of the Jeeps to bring back his grandchildren, Ellie says she's going with him. They didn't at that point know the T-Rex had escaped, so why does Ellie insist on going with him? Considering the Jeep has four seats and there's five people spread across the two tour cars, how did Ellie expect to squeeze everybody in?
Answer: He was sent to bring back the grandchildren, not everyone. If anyone else wanted to leave they could be picked up later when Muldoon was finished bringing the children to safety. Hammond was just concerned about them and wanted them to be with him. Ellie went with him to be with Grant, to make sure he is safe as well. So she would stay with him anyway.
Question: Why was Dr. Grant so dismissive of Tim when they first met? I can understand Grant being annoyed with the bratty kid at the dig site but Tim showed a genuine interest in dinosaurs and even mentioned he'd read Grant's book.
Answer: Dr. Grant doesn't like kids. Any kids.
That was an issue between him and Ellie Sattler, who wanted to have a family, while he did not. She eventually married someone else and had kids.
Answer: Grant just has a low opinion of kids in general. He probably thinks Tim is too young to really understand or appreciate the research that Grant has dedicated most of his life to. Also, Tim can come across as a little "too much" at times; he talks really fast and barely gives Grant a chance to get a word in edgewise.
Answer: After the explosion of the first Atomic Bomb, Oppeheimer was quoted as saying, "I'm not an evil man, but I have done evil things."