Though I don't know Marzzett's interactions with Thorawyn, watching him try to get back the scales was brutal when he was younger. The guy seems decently new (which in all fairness in CF could mean several years), and I personally never thought he was really one to whine to the IMMs. I also disagree with your idea of griefing. Seems totally normal for an outlander goodie shaman to do exactly what you're complaining about. Harass and annoy tf out of evil tribunals. I mean, it's not hard for you to just sit in your guild if you don't want your zombies summoned. I'd much prefer him wither and running and even giving you a chance to smack him in the head than the alternate route of camo hiding in his cabal forever. But as a necromancer who has to spend a long ass time getting new zombies, I get that that is annoying as hell. But I wouldn't go so far as to call that griefing, especially if you think you could kill him 1v1 given the opportunity.

You should also try taking the scales as a goodie shaman. Just thinking about that sounds absolutely horrifyingly impossible. So I disagree that the actions you've listed suddenly makes someone a "griefer and trash." I'm not saying he is or isn't, but what your listed reasons don't cut it for me.

As for the ghoul tunnels summoning, do you mean in Hamsah? I'm 83% sure that one of the two rooms with that name is actually not technically coded as a guild. So it becomes possible to summon out of that area. The room closer to the necro guild is the one that's part of the guild.