In a large skillet over medium heat, sauté the onion and garlic in the oil or butter, stirring frequently, until the onion is translucent, 3 to 5 minutes.
Add the ground turkey, beef, and sausage and cook, stirring with a wooden spoon to crumble any large chunks, until the meat begins to brown but isn't cooked through.
Add the scallions, half the cilantro, cumin, chili powder, salt, pepper, Tabasco, cayenne, jalapeño, and orange juice and cook until the liquid has evaporated, about 4 minutes, stirring occasionally. Remove the skillet from the heat.
Set out the meat, tortillas, tomatoes, lettuce, onions, guacamole, cheese, sour cream, and remaining cilantro and let guests assemble their own tacos.