The Question of the Greek New Testament

[Minimalist]

Yes, Greek was lingua franca throughout the east, largely because of Alexander's conquests, certainly among the educated elites.  Romans, when they overran Greece in the 2d century BC were culturally smitten by the Greeks and the upper classes largely adopted Greek language and styles.  This was similar to the adoption of French at the Sanssouci
Palace in Prussia in the 18th century.

It must be kept firmly in mind that literacy was rare in the ancient world and the numbers of people who could handle advanced philosophical texts was far smaller than even that number.