I’m aware of a PvP discord channel but if I had to guess raiding would be separate for the individual guilds. I don’t have the link for the PvP one but its been mention in a couple threads back I’ll see if I can locate it.
Found it! (I think): https://discord.gg/Mba3SJcvZA was the link from https://us.forums.blizzard.com/en/wow/t/the-wow-burning-crusade-classic-character-clone-service-is-retiring-soon/ no clue if that is an up-to-date one though