1. Italian mostly, with some small amounts of Lebanese, Polish, Mexican, British(ha) and Irish(potatoes). A lot of pasta, not a lot of things in casserole dishes.
Yup, not a lot of casserole material there, with the possible exception of the British.
2. Not sure, I think it's somewhere near the middle, but it's mostly him griping about unidentified frying objects from his in-laws. He's a bit of a snob/foodie.
Ah. From my time there, I remember the unique contribution of the UP to American cuisine was the pasty, a sort of giant, dry dumpling stuffed with meat, rutabegas, potatoes, carrots, whatever. Supposedly, it was imported from Cornwall, and miners would carry them into the copper mines and warm them over a shovel for lunch. I like them a lot, but they're hard to find outside the UP and northern Wisconsin.
3. Well, the food seems similar in terms of what's been described here versus what's been described by my boss, and I'm not sure where else it would belong...
Like Christology, defining the midwest usually tells you more about the person doing the defining than it tells you about the thing being defined.
I've always seen Michigan, Ohio and Pennsylvania as comprising a sort of intermediate zone -- which I usually think of as the "Old Northwest" for sheer lack of a better term. (That would be northwest US, circa 1800 or so.) Not really the tallgrass prairie states like Iowa, Illinois and Indiana, but not really part of the east coast, either.
.. and I'm not sure where else it would belong, except Canada.
Well, but for Ben Franklin's determination to acquire the copper on Isle Royale for the young United States, there it would be...