I am going to speculate that the 'EMT' bag was used as an emergency aid kit by the family and taken to the campground for that purpose.
I agree that no one should go without legal counsel when involved in such a serious matter as a missing child, if for no other reason than to have procedures and laws explained. It doesn't mean you can't cooperate with LE it just means that when you have questions you do not have to rely on LE's answers. The lawyer is on your side, LE is on the side of the state and LE has lawyers.
Questions no desperate, innocent person would even think of. Oh and lawyers hired by POI's aren't there to answer the parents' "questions". They are there to shut them up as prevent them from cooperating. Because that's what good criminal defense attorneys are obligated to do to prevent the parents from incriminating themselves.