Freddy also seems to hate fire as it is what the parents used to burn him alive.

Consequently, fire is one of the few things he fears. In his dream world, Freddy is invincible. However, when Freddy is pulled into the real world, he is the most vulnerable and can be killed.

Call of Duty: Modern Warfare II does support crossplay on PlayStation 4, PS5, Xbox One, Xbox Series X, and PC (via Steam and Battle).

Yes, all of the Call of Duty: Modern Warfare games on PS3 have a singleplayer campaign. Some of the campaign modes have a co-op mode, but I'm not sure which of the games has this. Call of Duty 4: Modern Warfare has singleplayer and multiplayer.