Loving all of your detail so far.
As far as your son, if it happened once, i can see. But twice suggests some type of issue. Was his name on his boarding pass EXACTLY the same as what TSA has for him? No missing commas or letters or anything? We have had precheck for a long time and when i use my frequent flyer logins that match my previous name( i have ID to match) i don't get precheck. My precheck is in my married name(also have id to match). So even though the date of birth and other info is still me....it doesn't give it to me. Also, since they use a funky letter/number combo,ie..1T8UKl... make sure the info typed in actually matched.