Place pretzel pieces in a food processor and pulse into pretzel crumbs the consistency of panko; place them in a shallow dish. Fill 2 more shallow dishes with flour and eggs and season everything with salt and pepper.
For the sauce, heat a saucepot over medium heat. Add butter and melt then whisk in flour. Add milk, let thicken slightly then whisk in beer and thicken. Season with granulated garlic and onion and cayenne. Remove pot from heat and stir in mustard and shredded cheese until melted and smooth.
Coat cutlets first in flour then egg and then breadcrumbs. Working in batches, fry cutlets in 1/8 inch of oil in a very large skillet over medium to medium-high heat until deep golden. Keep warm in low oven on wire rack-lined baking sheet.
Top schnitzels with a squeeze of lemon, some beer sauce, bacon, chives and pickles, and serve.