I would leave everything as it is. Let him get more used to you handling him if possible. Go in his room to work with that. Sitting on the floor to do so. Then try introduction to the most welcoming of your cats. Let them come to the gate and try swapping scents. Use a towel or some with the scent of each cat on it and put it with the other kitty. Eventually let the welcoming cat go in with him. Just a little at a time. If all is well, try feeding them together. See how that goes and post back. One step at a time.