Reasons for temporary madness

So Alex has been increasingly strange over the past couple of weeks and we're pretty much tearing our hair out trying to figure out what's got into him. Prior to this behaviour, he was progressing very well with new words starting to emerge and a very caring attitude for his little sis. This is our list of reasons in no particulr order:

Summer is over - less outside activity
Jaden is being mean to him
Jaden is a miserable bugger and he's just copying him
Lena slept in his bed and it smells different or something
Clocks went back and he's off kilter
He has an ulcer on his tongue
He has a cough and a cold
He's realized that Emma is, in fact, staying for ever
We shout too much
We're not strict enough
He's not getting enough attention
He's had too much attention
He's scared of his room now
He's bored of his room
He's frustrated that he can't communicate better
More teeth are coming
He's got growing pains
He doesn't need a nap during the day
He gets over-tired because we don't get him in bed at the right time
All of the above?