I agree with Chris on the CD's, Aloha. I have had pretty good results with how hard drive platters perform if you are going on the cheap for signals. You can usually pick up a number of nice new platters from junked desktop or laptop drives and jaz or zip disks. Look at the local computer shop, or even ask the local tech jockey if you don't have any of your own. The CD's just absorb too much light and are too flexible.

I would add very simple instructions to help reinforce what they've been taught. STOP, get warm, blow whistle 3 times, etc.

Practice with all of the gear, makeup pretend scenarios where they would use some of the FAK and some very simple and easy rules of thumb. STOP moving and get Warm or out of the sun if hot being the first the come to mind. So Chris is probably right about the compass as well, but it might help if they are trained to walk in a single direction until they hit water and then follow that water to civilization. But at 5 years old, I'm not sure they would be able to do that.

It's a nice kit! Looks like you tried to get them a good basic kit. You might want to add tweezers, some itch and burn lotion, extra socks and bug repellant. I'm curious how much these cost you to build (I think you had to make 25?).