Embarked on top of a cave site, discovered a refugee camp containing what's left of my civilization, then my expedition leader promptly declares herself Queen. The outpost liason lives in the caves underneath the house, and there are over a hundred "hostile" dwarves who have proclaimed themselves Barons and Generals living down there with them, being eaten by cave toads.

A few months in, the fortress is stable-ish and has the start of a metal industry. The Queen still hasn't been appeased, but at least we've hit rock in this horrible cave full of angry nobility.
I recommend if you try to get this fortress going that you try to get a militia set up in the barracks set on the side of the long tunnel west.

Either that or drain the ocean into the caves. Your choice.