hmm this doesnt really sound like any ocd symptoms i have come across, i doubt it could be ocd. the refusal to eat some food, could this just be because he doesnt like certain tastes or textures? the disruption of classes, have you looked into something called ADHD? attention defecit hyperactivity disorder, and children with this often do have tendencies of disrupting classes, outbursts of violence even though theyre usually good kids. you could look into that, go to the ADD board, pretty near the top of the list of boards.
anyway, give it a go, good luck and keep us posted! i hope you manage to find out whats wrong and then your son can begin to recieve the necesarry help