A secret government test places 3 children that have been raised with no human contact on a deserted island to see how they develop.

What were they raised by? It's cool but presently too vague.

The above critiques are really good.

My addition is that the logline does not quite make crystal if the trio have been raised together or completely apart.? (Which makes a big difference from a viewer empathy point of view.)

For viewer empathy to work on this situation, I think it is imperative that the three children have grown up and trained together so that they could at least be a viable team from the moment they are 'dumped' on their own.? Rather than acting like wary apes towards each other?in the first sequence of tests.

The situation isn't overly unique so the logline will need to really sell us on the characters. We should know who we are going to be rooting for and an idea of what their goal is going to be. Also, maybe consider giving?us a geological or political starting point - US government? UK? Russian?