In what ways does Dana explode the slave stereotypes of the "house nigger"? In what ways does she transcend them?
The most obvious way in which Dana transcends slave stereotypes, or indeed, expectations for all humans anywhere, is that she can and does travel through time. This gives her extensive knowledge of what will happen, making her a kind of augmented wise woman.
The other ways she transcends/explodes stereotypes are much more mundane these days. She speaks directly to whites as equals, she expects fair treatment, she retains the capacity for compassion, she carries a broad perspective with her, and she feels desire openly, with little concern for power dynamics.