Ok so I took the wand from Malwick on the newbie island. After I chose the dark path I get the quest to steal the tapestry. Well I read online after it was too late that it may be better to just eat the attack rather than get castle gloaming hostile.

So I am stuck with castle gloaming hostile. Apparently it takes 2 years to reset?

I can't enter Archibald's chamber/throne room to complete the breeding pit quest, so I am stuck without dark magic and unable to progress the story quests too.

My first thought was to empty castle gloaming of anything that moves, thinking that, like the attack on my castle, once everything hostile is dead the doors would unlock. Either something is hidden in a far corner somewhere or this did not work.

How do I get arrested, so I can skip time nicely?
Or can I "cheat" in some way, like force the throne room doors to unlock or force the zone to be friendly again? Resting for a yeah or so does not sound fun :S

You can kill civilians/guards. After you kill enough of them without paying the fine, you will get arrested for a year when you visit any throne room (queen Catherine in Erathia, Archibald in the Pit, etc.).

If you have a save point before the castle turns hostile. I think what I did was use the invisibility spell to steal the paintings, it would turn the castle hostile, but aslong as you don't touch the guards or have the spell fail, you should be able to get the tapastry as well as enter the pit. Like I said I think thats what I did, but I chose the path of light so I'm not 100 percent sure.