Some of the passages they have to go through are very tight and underwater, and diving equipment can get hung up or divers can entangle each other; the kids aren’t experienced divers and have to be taught how to breathe from tanks and even if they pick up the on-the-spot training quickly, there’s a huge risk one or more might panic or get confused trying to squeeze through these passages in water that is murky and maybe get stuck, blocking escape for the rest. After going without food for such a long time they are going to be a little weak. The rescuers’ll have to have a plan for anything that could go wrong before pushing ahead.
I hope the exploration team managed to figure out a way to get some supplies to them. They might just have to live under there for a long time while a slow dig (or enlargement of passages) goes on.
16 feet is NOT very deep, so the most dangerous aspect would be the narrowness of some of the passages.
They should bring the kids food to boost their strength, then have two SEALS guide one person at a time back through the caves, utilizing long air hoses, rather than have the kids actually wearing tanks.
The fact that the kids don’t know how to swim shouldn’t matter as far as moving them along the pathway, but often times such people panic when they put their faces in the water. For them I would suggest some kind of MILD sedative, enough to calm their nerves without making them drowsy. Again, 16 feet is VERY shallow for diving.