Oh, you'll have plenty of "local" and "flavor" in the city center.... Roma and Condesa are calmer and more upscale, and just a short subway ride away. For 3 nights, I personally would just stay in the same spot, whether that's in the center or in Condesa/Roma.
In season, you'll find huitlacoche anywhere and everywhere. Many places will have it "out of season" too; it's a common quesadilla filling, for instance.