So, four people:
crack c one
abusive messages one
tea party one
17 year old emoji one
plus that 35 year old with the DMs.
Potential for solicitation of underage images from the crack c one, but we don't have any confirmation that it occurred under 18. Possible malicious communication from the 2nd one. Lockdown rule breaking (is that still prosecutable? Hope not) in the 3rd. Nothing that I can see in that 4th one, apart from how silly is it to have any interactions at all with children you don't know on social media.
I can't imagine DMing someone who I knew to be a minor, it just wouldn't occur to me. I do note that the 17 year old seemed to be doing most of the messaging there so I wonder if HE was just trying to be polite- I would have shut it down all together as soon as I knew they were in education.
I was having a look at my work's company policy on social media. It's silent on DMs and focuses more on not posting inappropriate tit publically. However, I think we've all seen how public these DMs can become so I wonder if policies will be updated eventually. I'd be interested to see the BBC one, as they're dealing with public figures. I just can't see how the BBC will be able to allow him to carry on, so I really do think he's finished as a newsreader.
I hope his wife and kids are okay. This must be awful to go through even if they might have known at least some of it before.