Which players have played for Manchester United and Liverpool and Aston Villa and Nottingham Forest?

No player has played for all 4 clubs. Paul Ince has played for Liverpool and Manchester United as has Phill Chisnall. These are the only 2 players to play for both these clubs.

What about Ray Houghton?

Michael Owen

Peter Beardsley (he was signed by Man Utd but never made a first team appearance)