I don’t really see why this must be the case. Here’s my logic:
If Casey Opens Up to me: regardless of whether I see Good or Evil, I will EC to someone on Mission 2.
If Casey Opens Up to someone on Mission 2 and is called Evil: I will either Open Up to someone on Mission 2 or CF_Kane. It makes sense that if Casey is Evil, CF_Kane might be good? Not 100% though, so I could also EC to the same person Casey Opened Up to, or one of the others. I doubt two people on Mission 2 were Evil.
If Casey Opens Up to someone on Mission 2 and is called Good: I will EC with Casey to join the chain. Worst case is I am called Evil, know two Evils instantly, and have Kane backing me up (knowing Casey is Evil and therefore is less likely I am Evil). Best case we have a chain of three people of which I am almost surely Good (as that would mean the chain would include all Evils).
I don’t see how this is necessarily more messy than me Establishing Confidence first. I will admit, though, I did it this way because I would like more information before I do this (I very much don’t want to Establish Confidence with an Evil and be called that!) and because I can resolve them in any order I choose, and because I didn’t see a real reason to do it the other way.
So I guess the bottom line is I’m not sure why it’s easier if I did it the other way around. Perhaps an explanation would be helpful?