I do not think Totto can leave Mercedes without a proper continuity plan. The team will be lost like Williams was after Sir Frank stepped down as team Boss.
As for Hamilton and his comfort in the car, it seems some feature in the car is putting him off. He says something at the rear of the car. I think the aero balance is not what he is used to.
But he needs to adapt like everyone else. If it's something the engineers could have resolved if they were listening to him, then they really should take the blame for making a poorly balanced car.