Not all OEGBs have light colored legs. Some varieties like blue, black, self blue, etc. have dark gray legs. I would not expect them to be Dutch.
The two gray chicks are not silver duckwing, but they are probably OEGBs. I’m not sure about their variety, maybe self blue?
The chipmunk striped...
Modern Game Bantams are a great breed to show! They are very docile and easy to handle, and really stand out and look beautiful in the showroom. D’Anvers, Old English games, silkies, and Dutch are also good show breeds.
It looks like blue cuckoo something. Maybe if it’s an olive egger, it’s a cuckoo Marans or Plymouth Rock crossed with a blue ameraucana or something? I’m not sure, but it looks like it is probably a cross.
Cream Legbars are basically partridge cuckoo, aren’t they?
Also I agree, it definitely is not a meat chicken. It’s smaller than those Australorps, so it’s probably a lighter breed.
Some hatcheries have them, including ideal poultry I believe. However, those are very poor quality modern game bantams; too stocky and closer to old English games. You can look on the poultry show central online breeders directory to find breeders. Or you can visit poultry shows and meet...