You can make a steak pie with mushrooms and without kidneys if you desire. If you don't know how to handle kidneys, that's probably a good idea.
Learn to choose, trim and soak kidneys properly by grilling them, or at least cooking them in some uncomplicated way, before using them in a dish with a lot of variables. It's not that they're all that difficult -- but it's a good idea to learn to get the bitterness out and cook so they're tender before mixing them into something complicated.
Speaking of "pot roast," don't cheap out on the meat. Use something tender to begin with. The process is a sort of a braise, yes; but it's cut short by the relatively short time the crust can endure. Sirloin tip is ideal. If you want to get nuts, you could use fillet tail. Generic "stew meat" which is usually trimmings from the round and chuck are typically too tough unless you take measures during prep to tenderize. And so on...
An IPA (India Pale Ale) or ESB (Extra Strong Bitters) type beer goes quite nicely. Unexpectedly, so do Mexican beers like Tecate, Dos Equis and Modelo Negro.