So from my estimates we pretty much just have the two Bards left, who are still nauseated. Raoul could easily enough take them out I imagine. Or we could just toss them into the pit with the other goblins and be done with it. They're not going anywhere anyway.
Cade isn't going to be too keen on sacrificing the goblins. If he allows it, I imagine that would be enough to shift him to Evil.
He's Chaotic Neutral, so he's no goody two-shoes, but neither is he evil, and unless I'm mistaken sacrificing lives to some dark figure is pretty damn evil (Here, have these fresh souls! Now if you'll excuse me I'm late for volunteering down at the shelter). The Demon isn't a separate entity, either, just a fragment of his psyche that represents his more chaotic tendencies, while the Monk is the fragment representing his more morally neutral and disciplined tendencies. There's no way to have a dual-alignment, so Chaotic Neutral is the closest I get.
Now, as for that UMD check, the highest current DC is 30 to emulate an alignment, while the DC is only 20 to emulate a class feature. There are two ways to justify the UMD check for a relic, as we're going for. One is to emulate the item's requirement to worship a specific deity (emulating a class feature/alignment) and the ability to 'sacrifice a divine spell slot' (sort of a combination of activating a divine scroll/wand and emulating a class feature), or having the True Believer feat. If you consider the second one, you need to come up with the proper DC at which you can emulate a feat for the sake of activating an item (which could be further useful for other magic items, I'm sure). Maybe 20 + the minimum level at which the feat can be acquired? I'm sure there are other concepts that could work as well.