Season the meat and veggies with chili powder, coriander, cumin and tomato paste. Let the meat mixture cook for a minute or two with the spices, then add the beer and let that cook down for about 4-5 minutes. Reserve.
While the meat is cooking, make the cheese sauce: In a saucepot over medium heat, melt the butter. Add the flour and give it a stir to combine with the butter. Cook for a minute or so then whisk in the milk. Cook until thickened.
Drain the can of tomatoes with chilies and add them to the thickened milk mixture. Fold in 2 1/2 cups cheese and the reserved noodles. Season with salt and pepper, and reserve.
In another saucepot, heat up the can of refried beans with a little bit of water.
To build the casserole, spread the beef mixture out in the bottom of a casserole dish. Top with the refried beans and finish it off with the mac and cheeses and the remaining cheese. Pop the casserole into the oven and bake until golden brown, about 15-20 minutes.
While the casserole is baking, make the salsa: Mix the plum tomatoes, remaining jalapeño peppers, red onion and cilantro in a small bowl. Season with salt, lime zest and juice, and reserve.
For the guacamole sour cream, scoop the flesh of the avocados into the bowl of a food processor and add the sour cream, lemon juice, remaining 2 cloves grated garlic and hot sauce. Process until creamy.
Once the casserole comes out of the oven, top it with the crispy corn strips and shredded iceberg lettuce. Top with the salsa, then the guacamole sour cream and finally the chopped olives with pimientos and scallions.