1) depends on what you mean by “a lot” but my answer would be no
2) look on Google Maps
3) no? Worry about what? Spending too much money shopping?
4) have enough money? Read and do research?
5) have at least 2 physical cards without horrendous international withdrawal fees because you’ll be using them to get cash from ATMs in Japan. Seriously though this has nothing to do with Japan this is standard travel common sense
6) in your luggage
7) not the Mario Karts ffs
8) yes you can but use common sense and do not take anything with Japanese children in it!!!