From my point of view the first face seems to be cheerfull girl. Talkative but a bit sarcastic.
The second face, it's a bit different, that boy seems to be a bit selfish. Also we can see he's cheerful but not as cheerfull as the first one.
The third face, in my opinion we could define as a moody person, but sensitive. She's not selfish of herself and need the others aprovation.
The last one, we could define this face like a proud and selfish person, calm, calculate and a bit unemotional.