Actually, the terms used in the New testament are directly the latin terms used by Ceasar AUgustus. The hebrew translations into Latin (and then english) was sort of retrofitted.. and whne there were multiple words to use with similar meanings, 'salvation' and 'savior' were chosen, even if they were not the best fit for the Hebrew.
The Jewish faith got the concept of Satan and dualism from the Persians.
And no, the 'messiah', according to the Jewish texts, was not supposed to be 'god made flesh'. That was a Christian concept that came from the Greek gentil converts. The Jewish expectation for the Messiah was just a man who would kick the foreign invaders out, and become a home grown king over Israel.