Had God revealed that Christ's death, burial, and resurrection provided salvation for the whole human race at that point?

No. At that point God had not yet revealed that Christ's death, burial, and resurrection provided salvation for the whole human race. Scripture indicates God keeps things secret until His chosen time, and He was still dealing with Israel on the grounds of the covenant promises.

Les explains that God had not yet revealed the secret of all His purposes in Christ's going to the cross; that revelation would come later. God is sovereign and has the prerogative to keep things secret, as Deuteronomy 29 states, and He keeps things secret until He reveals them. When He reveals it, He expects mankind to believe it. At that point, He had not yet revealed that in the death, burial, and resurrection was wrapped up the salvation of the whole human race, but He was still dealing with Israel on the grounds of those covenant promises. In Acts chapter 7, Stephen reviews Jewish history from the call of Abram through the Law and Christ's coming to proclaim Himself as their Messiah, and the crowd is ready to put him to death when he lifts up the name of Jesus of Nazareth.

Was the salvation of the whole human race revealed at the death and resurrection of Christ?

No. At the death, burial, and resurrection of Christ, God had not yet revealed that the salvation of the whole human race was wrapped up in those events. He was still dealing with Israel on the grounds of covenant promises. That secret would come a little later.