Is it confirmed that the Black Bow of Pharis is required for the weapons achievement? This is the first list I've seen it on, and I believe she has a tendency to roll off of cliffs...I'm pretty sure she is gone in my game anyway.
Also, I'm worried about finding the invader Leeroy, too. Do you have to summon him for Pinwheel, and what if he rolls off of a cliff? Will he appear if you've already killed Nito? Do you just have to hope for the best in the next playthrough?