With Claudia Lawrence I think the Police do know who it is but they haven't got enough evidence for a conviction. She was seeing quite a few different men and its obvious that either one or more of them have got jealous and done away with her. There's no way she was just kidnapped off the street by a random stranger.
With the lad in Doncaster who went to London, I think he will have met with a paedophile in London and been murdered sadly.
Corrie McKeague I think ended up on the landfill site, he shouldnt have got so drunk that he was sleeping in bins etc, that was self inflicted unfortunately.
The Corrie Mckeague case hauntEd me, for a long time after that I couldn’t sleep when my brother went out on a night out as he was the same age and did tend to get mortal drunk! I’m from Doncaster, I live next to the school he went to and it’s just so sad, people still think about it to this day, did you read about the boy who appeared on a reddit type site last year asking for money after his partner had walked out. Called himself Andyroo or something and the missing boys parents called him Roo! He said he didn’t have a bank account because he was a runaway/was too young when he left home not 100% sure. Despite reading this though I do think he’s sadly dead