I have had issues where I can see someone in Friends in the game but they cannot see me (they need to see me so they can get the 2 online trophies). I get them to set Matchmaking to Friends Game and then join their game. While still in the game they press PS button and delete me as a friend. I then press the PS button and send them a Friend Request and when they accept it after a few minutes or so they can see me in the Friends menu in the game. If not then we both restart our playstations and restart the game and then they can see me in Friends. I have done this with 3 people so far that could not see me in Friends and it worked each time.