None of them have been written in coloured crayons, so that rules out at least half the first team squad. There's only a few left I can think of. Maybe Yoshida and JWP did all six between themselves.
Clockwise from top left ... The artist formerly known as Prince, Someone beginning with J, a Modigliani sketch, a Gerald Scarfe cartoon of Margaret Thatcher and Peter Osgood ??? Any help? Still a great gesture though