Regarding Johnson's call up to the USMNT - he is one of four goalkeepers. The other three, Guzan of Atlanta, Gonzalez of Dallas and Steffan of Dusseldorf, do not have any games during the international window. Johnson is the only one who will have to miss games because of being called up.
That, combined with the fact that Berhalter called in 4 goalkeepers instead of 3, suggests to me that Johnson might get released after the Mexico game on Friday. Johnson is the solid #2 with the USMNT, so his call up makes sense. This keeps him involved with the team, but he doesn't have to stick the whole week to get a lot of benefit.