Spread the pecans on a baking sheet and bake until lightly toasted, about 7 minutes. Cool completely, then very roughly chop.
Mix the sour cream, heavy cream, lemon zest and juice together in a large bowl along with the ancho powder and 1/4 teaspoon salt. Add the pineapple, oranges, pomegranate, marshmallows, coconut and pecans and toss to combine. Serve immediately or refrigerate until ready to serve.