Cool! You were there and witnessed the fact the Apostles didn't talk to them! Wow! Awesome! (I knew you were a gramma, but I didn't know you were that old! You rock!)
Well I am GETTING OLD but mostly I read the word for myself :>) And it is clear that they OBSERVED a conversation between Jesus and the witnesses
In the Jewish law things were confirmed with three witnesses...Interesting the Law and the prophets testified with Jesus who He was..and the apostles were the witnesses of the meeting
Mat 17:2 And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light.
Mat 17:3 And, behold, there appeared unto them Moses and Elias talking with him. apostles were the human witnesses
Mar 9:4 And there appeared unto them Elias with Moses: and they were talking with Jesus.
Luk 9:30 And, behold, there talked with him two men, which were Moses and Elias:
Jhn 1:17 For the law was given by Moses, [but] grace and truth came by Jesus Christ.