What are you talking about? The GMs work out of the Austin office on tickets. At home right now, but I don’t know why you think they are “RPing” on a forum. You don’t even know who the GMs are! They don’t post on the WoW forums.
As has been explained, there is no evidence unauthorized access occurred to your account. You have an Auth on it and that can’t be bypassed without them cloning the device.
Actual hackers destroy your account and sell it off.
Yes you can now. It does require ID of course to prove the person is the account holder.
This post on what GMs handle and how to reach them might be helpful
https://us.forums.blizzard.com/en/wow/t/spotlight-on-game-master-help/11354
They are reached via ticket.
The forums are a place for players to interact. This one serves as an Information Desk where players can get information on how to use the Support system, find Support articles, get info on policies and procedures, get info on how various services work, etc.
There are Forum Support Agents (who are not CS or GMs) who oversee it during work hours. They ensure that the info players provide is accurate and correct it if needed.