In the book, the character Nick does not exist. Instead, there is a genius professor that is constantly going into battles of intelligence with Ian Malcolm. Also in the book, Kelly has absolutely no relation with Ian at all, Sarah is the last to get to the island (unknowingly with the bad guys), the professor is the reason they go to the island, and, as far as I can remember, Hammond doesn't make any appearance in the book.
The names of Roland Tembo and Nick Van Owen are references to the main characters in Warren Zevon's song "Roland the Headless Thompson Gunner".
About the book really, but it sort of relates - in the book of Lost World, Malcolm is a main character (like in the film), despite the fact that he dies at the end of Jurassic Park, the book. It's semi-explained away at the beginning when he's giving a speech and says something like "rumours of my death are greatly exaggerated", but even so - at a guess Jeff Goldblum had already signed up for a sequel...
The Mercedes ML-320 used in the film were provided not only to show off the upcoming release of the M class vehicle but were also modified to be convertibles, something that has never been offered as an option since the vehicle's release.
When the bus crashes through the video rental store, one of the signs that are knocked over is for a movie called 'Tsunami Surprise'. There is no such movie. All other signage in the building is for movies that exist.