As the title says. You may pick only the major characters, or include all the minor ones too, as you choose.
4. The Montana kid
6. Sattler's unnamed baby infant
8. Gyrosphere teen operator dude
Lex first because first and foremost she seems like a real little girl. She's like the sister I would have always wanted. I like Crichton's book version too, as that Lex is very natural as well in her constant crying and all, but for a movie this more calm and older version is more suitable as constant moaning would have made listening to her obnoxious. She can still act terrified and panicky, as proven by not only the road attack and afterwards when she's still shaking of Gennaro's betrayal, but she can get it together quickly. And she has personal traits such as the vegetarian and "hacker" things, both which come in to play. Ariana Richards is also very natural actor and I love her as person in real life too.
Much of the same also applies to Tim, and his dino nerd enthusiasm is nice opposite for Lex who doesn't really care of dinosaurs. Tim's also part of two action scenes that have nothing to do with dinosaurs (car in the tree + fence) which makes him unique character in JP franchise. I rank him lower than Lex for one thing though... And no I'm not really talking of how he's "indestructible" like Jurassic Park Podcast people would say, but because he doesn't pick up the damn gun at the control room floor! Timmy you idiot
Cathy Bowman at the start of TLW is prime example of how you should write a kid actor for minor role. Not obnoxious, not unrealistic. And they go straight to the point with her, there's a reason why they had to had kid for this one. Really good little actress. Honestly she should've been the only kid in the film (well, other than the Lex/Tim cameo moment)
The Montana kid at the start of JP doesn't really do much but the facial expressions are spot on. Once again, like Lex and Tim he acts like a real kid when Grant starts telling his horror story, and that's all I ask.
Eric Kirby is all right, you hear me! He's all right. Of all the major kids in the sequels he does the least harm. I mean, I still don't think he should really be there, because not every film needs to have kids character just because. The script could've easily been modified not to have kids. But, but, for what he is written to be, he is alright. That's not to say I like everything he does (like singing the stupid Kirby ring tone) but there are no real big drawbacks I can think of? His chemistry with Grant seems natural and you can sort of believe he might have survived there alone for so long. Well at least almost...
Sattler's unnamed infant baby does nothing and is therefore automatically better than kids below.
Kelly is the first one on this list I actively do not like. She's not quite as annoying brat as the one in the book (and thank god Arby isn't here at least), and Vanessa Lee Chester is a fine actor, but other than that there's not much to be celebrated. The gymnastics scene is pretty awful, but even more terrible is the bit she has with Malcolm on the mainland. She bitches about Malcolm never grounding him, wtf? Then whe she is on the island, she literally does nothing and is completely useless. There's very little plot device with her and she might as well not be there. The only thing she has going is the substitute mother relationship with Sarah, but that's about it.
The JW gyrosphere operator dude, whatever his name is, is meant to be stereo typically annoying, and it works. Also, would they really let someone like that in charge of those magical balloons in highly dangerous environment? This isn't exactly like ferris wheel or children's train. [[[At this point, since we're talking of the people in the park, I'd also like to give honorable mention to the petting zoo kids who are effectively killing off all the apatosaurus babies and other little dinos, but I'm not ranking them since they are multiple people.]]]
Zach is someone I'd like to punch in a face. I mean both the character and actor. He, like half of the characters on this list also shouldn't exist. The reason he's not at the bottom is because at least he has a story arch of sorts, even if not great.
Charlie single handed ruins the Spinosaurus river scene with the stupid Barney attics. THANKS CHARLIE. DINOSAUR MAN COULD'VE DIED.
Finally everything about Gray is terrible.