Regarding the two little daughters: The older one seems completely un-fazed by the PE teacher's treatment of Jo. I did wonder whether Jo might be her step mum. And further, whether Jo was an already pregnant "troubled teen" that PE teacher latched on to (as PP described above is a pattern he is now repeating with Ryan) and took her on as step mum to his daughter, with the promise to bring up Jo's daughter, Poppy, as his own. But he isn't doing so in a good way, because he's cold towards Poppy, and Poppy is clearly scared of him, hence the coat kept on - a subconscious ready to flee/protective instinct, maybe.