Is it everyone in the picture or only the ones you mentioned because Ban Mido, Medaka and Seiya are disgustingly above the everyone else here.
This is actually a decent matchup IMO, the Sins have superior stats in a few areas but the Warlords have ample hax to counter.
Ban's immortality can be countered by Hancocks petrification, and though he has superior speed, her precog and physical ability should allow her to keep up. Kuma basically has Mel's counter but can use it more objectively and can himself move faster than anyone here, he can effectively counter King's abilities and or BFR team 1 at his leisure. Finally Mel and Don would be a close match that could go either way but I think Don is well suited to handle him at a distance, especially since he can immobilize physically imposing characters rather easily (Ex. Jozu).
All in all it can go either way but I'm leaning more toward the Warlords for this one.