I don't understand why Cauldron is a massive threat (new to the thread, my apologies if it's been covered) - Joe is generally aware that the source of the powers is a problem, and he's approaching the weight-class of "people who could plausibly wreck an Entity's day". In theory they should be able to reach a negotiated arrangement once someone tells him that Scion is the cause of the problems.
The passenger has the views most common to that fandom which for Cauldron likely means it sees them as pointlessly cruel idiots and it certainly doesn't like them. More generally Joe's precog countering at that point or rather all the way until he got ocp at the rock meeting was limited to his perk gains being unpredictable and them introducing new stuff that the precog shards lack data to model. Due to this he was vulnerable to Contessa stopping by and manipulating or strong-arming him for a while. Joe's personality and views also means he really wouldn't like stuff they get up to like leaving the Siberian free hoping to drive people to the prt and to use vs scion or their treatment of the case 53s.