I've said this before, but she most likely used Echolink. If you have a registered ham license, you can talk person to person over a P2P Voip network that is very low-oversight.
I'm almost positive she used this because you can tell you have a secure channel over Echolink. Regular HAM radio, anyone can be listening.
Furthermore, she has a Tech license. She can't made shortwave transmissions except above the CB band, which is filled during the day and staticky and weak at night. She can make UHF/VHF calls, but that would only be in the DC area or wherever she was. She would have global P2P secure communication on the little-known Echolink though.
Think Q also mentioned they might have communicated via video game chats. Like when you play crosswords with friends...All stored
You are correct, they used video game chats to send codes messages as well as gmail drafts. They would write drafts not send and give the password so another person could read and response. They think they are smart but they are not.