Check out Ratmen Weapons Teams for a few weapon ideas for Warjaks. They can take a Flamethrower (12", A6, AP(1)). Hope that helps!
Ah! There they are! Thank you!
Flamethrowers (12", A6, AP(1), 20pts), and also Poison Bombs (for Crucible), and Gattling guns (20pt) for Cygnar, Weighted Nets (for the Pirate Jacks), Pavise Shields (+2 Def) for any Jack with a shield. Claws (A3, AP(1)) which would come default on all jacks (maybe small claws for light WJ?).
And I could model them on Rat Ogres, and Storm Ogres, but make them Constructs.
WM works really well for this I think! Less sure about the infantry, but I'd use khazil's innovations for that.