What time of day is the wedding?
Are the "boys" and "girl" adults in the wedding party, or actual kids?
Generally what'd work is for the men to wear black tuxes with a splash of color (cummerbunds, handkerchiefs, that sort of thing) and then women wear more of the color (solid lilac dresses for example, or "beige" [maybe more "cream"?] with lilac accents). The type of wedding has a lot to do with what sort of dress they would wear.