None of these conversions were absolute. Moreover, you missed a rather important one: the Hellenic/Greek era of the Ptolemaic dynasty, from which we get the still-spoken Coptic language, which was formed from a mix of Ancient Greek and the indigenous Demotic Egyptian language.
Language is not race, but it is strongly intertwined with ethnicity and culture in most parts of the world.
I pointed out Roman for that reason, as middle-late Roman culture itself was largely derived and built on top of Hellenic influence. Just look at how different Etruscan and early Roman civilization was compared to Rome after the Macedonian and Achaean wars
The Greeks had a lot of influence over the Romans, and the Romans even conquered Greece, but Hellenic Egypt was not the same thing as Roman Egypt. The rather tumultuous transition alone is one of the most famous historical events, though most people know the names (Cleopatra, Antony, Caesar) more than the context.
This seems like a bizarre statement, or at the very least your thesis does not seem supported by your example. There is no particular reason to think that Roman civilization should be the same after the passage of 500 years since the supposed founding of Rome. Ascribing that in any significant sense to Hellenic influence seems ill-founded; there was a massive difference in fighting style, and hence military virtues, in societies where military virtues were all-important. Also, as far as I know (which is admittedly not a great deal), early Roman combat and armament was more similar to the hoplite armies than later periods. Perhaps you can allay my ignorance here.
Language is not race, but it is strongly intertwined with ethnicity and culture in most parts of the world.