sorry. no slams for fed reery. there is an outside chance for fed at wimbledon but he has to be in the same side of the draw as NoDjok. and NoDjok would have to be a little off.
then, and only then, can fed finde himself in the final. once there, it is anybody`s ball game.
i will answer the rest of your question later.
Mr. CD, if the US Open is back to being faster, like pre-2010-2011, he is always going to be a definite threat there. There were many complaints last year about the slowness of the court, sometimes the tournaments react to those comments. Even if it isn't faster, he's still a threat, but he needs better luck and more toughness than the last couple of years. I think he has become tougher the last few months, but needs to carry that into the US Open.
At Wimbledon, I agree that a favorable draw would help as you said, but even better would be if the weather gods help him. Intermittent rain and cloudy weather would keep the dust down and the base from baking hard in the sun, and the consequent high bounces once the grass wears down in the second week. If that happens, he is very dangerous there, but it's probably only a 1 in 6 chance.
At Roland Garros, he's a threat to win only if Rafael Nadal goes down somehow.