Lightly sprinkle the cod with salt and pepper. Transfer to a wire rack set inside a rimmed baking sheet. Chill, uncovered, at least 1 hour and up to overnight (this air-dries the surface so the batter will adhere better to the fish).
Whisk the flour, cornmeal, seasoned salt, paprika, baking powder and baking soda in a medium bowl. Add the beer, club soda and vinegar and whisk just until combined and no lumps remain.
Fit a large heavy pot with a deep-frying thermometer; pour in oil to a depth of 3 inches. Heat over medium-high heat until the thermometer registers 375 degrees F.
Working in batches, dip the fish into the batter, allowing excess batter to drip back into the bowl. Lower the fish carefully into the oil and fry until light golden brown and just cooked through, 3 to 4 minutes. Transfer to paper towels to drain.
Serve the fried fish with the warm tortillas, pico de gallo, hot sauce, pickled vegetables, lime wedges, avocado, cilantro and cabbage.
Kiwi and Tomatillo Pico de Gallo:
Toss the tomatillo, kiwi, lime juice, basil, serrano, garlic and onion in a small bowl to combine; season with salt. Cover and chill 1 hour to allow the flavors to come together.
Carrot Habanero Hot Sauce:
Puree the carrots, lime juice, salt, garlic, habanero and 1 cup water in a blender on high speed until completely smooth and no large chunks remain. Transfer to a 1-quart jar or nonreactive container, cover loosely with plastic wrap and poke a few holes in the plastic to allow the hot sauce to breathe. Let sit at room temperature for at least 24 hours before serving and up to 3 days. The hot sauce can be made 1 week ahead; chill after 3 days.
Mexican-Style Pickled Vegetables:
Pack the chiles, carrots and onion into a 1-quart heatproof jar or a nonreactive container. Put the peppercorns and allspice berries in a dry large saucepan over medium heat and toast, tossing constantly, until just fragrant, about 2 minutes. Add the vinegar, sugar and salt and bring to a boil, stirring to dissolve the sugar and salt. Remove from the heat and stir in the lemon zest and juice, oregano, garlic and bay leaf. Let cool slightly, then pour the brine over the chiles, carrots and onion to submerge. Seal and chill at least 3 hours before serving. The flavor will mellow as it sits. The vegetables can be pickled 3 weeks ahead. Keep chilled.
The longer this hot sauce ferments, the better it's going to taste. If you're new to fermenting, this is an easy recipe to start with, and you can taste the difference in flavor every day. Sure, it's great as a fresh sauce, but by day 3, you'll see what we mean.