just my two cents, (i dont mean to sound insensitive in any of these)
Amy Lynn Bradley - i think it's glaringly obvious that she unfortunately fell overboard. in fact, i personally dont even class this as an unresolved case. the sex trafficking thing is very far fetched. no proof, dodgy sightings. very sad and horrific, but there is no mystery here
corrie mckeague - another one, no mystery here, he was drunk and decided to sleep in the bin. he got taken to the landfill, they may never find his body. i personally don't class this as an unresolved mystery either, the parents just obviously don't want to accept that their son would do something so irrational.
maddie mccaan - absolutely no evidence or reason to even think that the parents are involved. they are blatantly not, they would have been charged or at least caught by now, it's been years of extensive analysis. they are guilty of course for leaving the poor kids alone in the room, but i would eat my foot if it came out that they had something to do with it.
i cant remember the exact quote i read but i have been obsessed with unresolved mysteries for a few years now, and it's almost ALWAYS the most obvious outcome that is the truth as to what happened. these are obviously just my opinions but i've loved reading these threads <3