@Wandering Sentinel - I second your thoughts, but the anarchist path is currently my favorite because it doesn't lock you out of any areas; if it was changed to do so, it would be quite a bummer 
Indeed, so I don't know why you're bringing up insultsYes. They threw a fit when I suggested they work together and just remaining quiet during the argument before the final attack leads to something that results in Ashe more or less threatening to kill Nerat. Choosing to side with the Disfavored causes Nerat to go ballistic and appearantly try to kill you and Ashe. I have no clue what Ashe does if you side with the Chorus, but the obvious assumption is he flies off the wall as well. Act I is set up entirely to cause them to be at each others' throats and you can't finish it without angering someone.
Once you get the artifact you can ask the Beastwomen's Prima how to get to where Cairn is, and she'll unlock the map for you. Once there, just make your way to the Spire and you'll get to kill Cairn.
Yes. They threw a fit when I suggested they work together and just remaining quiet during the argument before the final attack leads to something that results in Ashe more or less threatening to kill Nerat. Choosing to side with the Disfavored causes Nerat to go ballistic and appearantly try to kill you and Ashe. I have no clue what Ashe does if you side with the Chorus, but the obvious assumption is he flies off the wall as well. Act I is set up entirely to cause them to be at each others' throats and you can't finish it without angering someone.
Didn't see it mentioned, but with regards to the original question, the Disfavoured pathway allows you to do every Edict; however, when given a choice between Lethian's Crossing and the Burning Library after sorting out the Edict of Storms you must choose the Burning Library. If you choose LC, you're locked out of the Library.