Jamie Vardy was named on the substitutes' bench for a PL match for the first time since March 2015, but after Christian Benteke struck the crossbar with a header early on the Foxes took control.
Musa broke the deadlock with his first Premier League goal for the club, scoring from 20 yards having linked up well with Islam Slimani.
Okazaki made it 2-0 after Damien Delaney's excellent diving clearance fell to the striker.
And after Kasper Schmeichel denied both Wilfried Zaha and Yohan Cabaye with point-blank saves, Fuchs extended the lead with a rifled effort from distance.
Cabaye netted a consolation for Palace from Wilfried Zaha’s cross late on but it proved to be a happy afternoon for the PL champions.