>>, but Ghana cant be used because it wasn't known as Ghana at that time
Good catch. "African warrior" should cover it for the purpose of the logline.
The passivity of the protagonist and the others in "12 Years a Slave" bothered me too, but given the historical context, I can understand why most slaves submitted. Slave rebellions were ruthlessly repressed. If slaves managed to overthrow their masters, where could they flee? Where could they find sanctuary to stay free? Getting back to their homelands in Africa was an insuperable obstacle.
But there were a number of rebellions in the U.S. and in Jamaica, as you well know. I worked with a writer on a script based upon a slave rebellion in Florida after the War of 1812. Which, as did they all, came to naught. They won their freedom temporarily only to have no sanctuary to find peace and freedom.
Which is the one big question I have about your story: How do they find passage back to their homeland after they've overthrown their masters? With the ticking clock running: the British would be expected to counterattack fast and furiously. No time to loiter.
But I assume you've got that figured out in a way that is true to the historical period. Best wishes with your story!