In the old days of tennis none of the players had coaches.
Federer doesn't seem to need a coach as much as others because he is so smart in seeing what tactic to use against different players. He has a great Australian coach when he was a junior and that laid the foundation he has today.
As for who he practices with, they mentioned that he practiced with Shalken earlier in the tournament. He also tends to practice with other Swiss players.....which who knows how much help that is.
As to the question of his training......on Federer's website there are photos of him working out with a heavy ball and ballance bar. He also was running on a treadmill. He doesn't appear to lift heavy weights to build up muscle.