Bring anyone. Guild are fairly poor compared to Arcanists.
Not sure I've ever lost vs guild whilst not playing them myself.
Kaeris can be ok vs sonnia. Don't set your own people on fire, take purifying fire for the pyre markers, kaeris, firestarter, hank and Cerberus are all fast enough to get to sonnia turn 2 at the latest, kill off Frank with the Cerberus.
Have fun crushing the fascists with your comrades!