So he is smart enough to burn the apartment, but not burn her body inside which would destroy evidence of cause of death and he rather leaves body letting outside for police to find out and imitate serial killer?

I mean if you don't wanna burn her then why not bury her (much better solution long term)? Seems much safer than leaving body outside for anyone to find.

Also John was really unlucky to land on the car, so it's safe to assume he survived, right?

They also never explained why people saw at all serial crime places white van (extremely common, so it's proof of nothing really), but not small red Peugeot, which is pretty rare and people should remember it.

First for episodes of S01 were amazing, but then it went quickly downhill and whole S02 was already pretty big disappointment with meaningless conversations (whole sister Clare storyline was pointless). They also never explain why was teacher preparing Molotov cocktail and it would make much more sense, if she kidnapped him in middle of the season, otherwise again pretty meaningless storyline (yeah we get it, he is hated kid and will prolly end fucked up).