The way I understand it was the 70 scholars were gathered together with the Hebrew texts and the Jews spoke with the translators to pick the most descriptive Greek word that matched what the Hebrew said. Scribes and Pharisee's had studied the Scriptures for thousands of years to set the meaning of what was given. They would describe what they believed the phrases said and chose the Greek that best described it. In my studies, I use several sources to decide what is true. For instance, Nimrod was said to be a good hunter, but what seems to be lost to Christians that Jews believe is that he was a hunter of men, not animals. Reading a Jewish study Bible differs in many instances of what the generic Christian is taught. The Scriptures are perfect, but the translations is where we find differences. If we just want to read a Bible, many will get the meaning across to the reader, but to STUDY the Bible, we need to get as close to the original as possible. The vast majority don't spend our lives studying Hebrew and Greek with Aramaic thrown in. Some trust has to be formed along the way.
I don’t think there were 70 Aramaic scholars available.
If you get “as close to the originals as possible”, you’ll find quite a few additions, deletions, transcription errors, and other such things.