I must take exception with your view of James 1:2. (The only exception I take in your post, BTW) Given what we think we know about early Jewish-Christian congregations, the acts of favoritism/discrimination were most likely perpetrated by men.
I think you may privilege the formal authority structure over the informal here. I lived as a child in groups where the authority was entirely male in a formal sense, yet you would see the hierarchical structure reflected by the women. I expect you’re right that the formal act of asking someone to sit here or there was done by the men. I just doubt that the women did not become involved in similar behavior.