Hi Willie,
I don't really want to get into linguistics, because it's not really an area I'm adroit in. However, Aramaic, the way I understand it is a semitic language common with the ANE (ancient near east). As such, it is the foundation in which the Hebrew language was constructed from and that which a sections of the OT and NT were written in. As it pertains to Jesus, select writings in the OT / NT, you can't really say there was a significant difference between Aramaic and Hebrew.
Furthermore, Kione Greek was the common language, so it would not be uncommon for Jews to be fluent in both Aramaic and Greek. Actually, more Jews knew Greek and didn't know Aramaic (Hebrew) which is why the Septuagint was so popular. This can be seen by the writer of the book of Hebrews as it references the Septuagint, not the Hebrew version of the Bible. This can also be validated by the Jewish writers who complained that their original language was dying and were making a call back to the Hebrew language.
As such, I think a better way to say which I've quoted you as saying would be to state: Jesus would have been fluent in both Aramaic, Hebrew and Greek. He would have also been aware of both Hebrew and Greek culture.
This would mean that Jesus understood the Hebrew word Sheol (He would have had the entire Bible memorized verbatim with commentary) and he would have known of the Greek god Hades, who was the brother of Zeus. With a set of 21st century eyes, it's pretty easy to see that there is a vast difference between Sheol and Hades... So to say Sheol is Hades, well... I don't see how you can make that connection unless you completely disregard the cultures and the world Jesus lived in.
Finally, Jesus uses the word Gehenna and he uses the word Hades and I believe those words were accurate. If you haven't, you should do some digging on the location where Jesus said, And the gates of Hades... find out who the patron God was in that area and ask what good little Jewish boys were doing there. finally, dig enough and you'll find that there was a crack in a rock in that very location. I believe it may have been where Hercules was written about? But I'm not sure. Anyway, you will find that it was where the gates of Hades was said to have been. This is why I don't see a problem with Jesus being at that very spot as using the word Hades. Make sense?