Base on IGN gameplay, I don't think I heard them talking to each other during exploration. Is that mean Greedfall have no banter at all OR they just cut some spoiler from gameplay (see that they cut some scene before sneak past creature).
And I wonder how many line companion have during battle. So far Kurt only have on line (and gamer already make joke from it).
Petrus have at least 2 and Siora have 3.
Maybe Kurt have additional line in other condition like Siora that suggest player drink mana potion.