Yes! The white is the only one that doesn’t have feathered legs.The buff looks like a frizzle buff Cochin.
The white one and the black one could be old English game bantams.
The other could maybe be a dark Brahma bantam, but not sure. Does it have feathered legs?
White OEGB, Red Frizzled Cochin Bantam, Dark Brahma Bantam, and Black Cochin Bantam!
OP, it's too early for gender on these birds. But I would keep an eye on the black one.
Repost at 7 weeks or so if you still need help with genders.