Bungou Stray Dogs 2nd Season Ep.08

The quote basically means that the mind maybe cloudy, but never your gut (feeling). 

Mark Twain with his ability Huck and Tom. Teaming up with Port Mafia seems to be the most logical way in this situation. I also think that Port Mafia will accept to protect their city.

Moby Dick as a flying fortress, why not right. 

Even though they kill people, they are protecting their own city. Maybe it's one of the factors that lead to Atsushi wanting to team up with them.