How about “The Free Men” as one of the companies to inspire a banner, They were originally a group of peasant rebels fighting against the oppression of a cruel lord, but when their cause failed to gain support they eventually turned to mercenary work and occasional banditry.
Their banner would have peasantry iconography, maybe crossed pitchforks (scythes or other farm implements turned into weapons), with a bushel of wheat or something similar to represent their origin, and a broken crown to represent their contempt of, and rebellion against authority. The company isn’t really interested in justice as much as rebelling so symbols of justice I think would not be great for their banner.
Probably muted colors, grey, brown and the like would best capture the spirit of this company.