I'd tell them that to continue playing as they have is putting their futures here and elsewhere in doubt. Would any scout be recommending more than two of our players as any sort of target based on the last month's efforts? Never mind what happens when a new gaffer looks at them with a dispassionate eye and sizes up who gets to stay past April!
I'd put players in their proper positions as far as possible - injuries and suspensions allowing - with emphasis on the wide men staying wide, going past their man and putting crosses in.
I would drill into them that if we are in possession and they aren't on the ball, that isn't an excuse to have a breather - it is an opportunity to run into some space and make themselves available. And if we aren't in possession then constant back-pedaling if anyone runs at you is not the thing to do - you don't have to dive in, but at least get close enough to stop a cross or shot.
I'd reorganise the defense at set pieces - no zonal marking, a man on the posts if needed and leave at least one player up: preferably one who can hold the ball.
I'd tell Obika that he is more likely to win a header if he jumps for the ball, Thomas that he is more likely to win a ball if he doesn't deliberately get himself the wrong side of his man.
I'd tell Mehmeti and GvK to go out and buy some milk, then change the locks when they were gone.