Q1: At a snack bar do people have to eat food standing?
Q2: Do you have sandwich stands which sell sandwiches?
Q3: Do you have noodle stands as well? What is the suitable restaurant name which sell noodles? Noodle houses? What about 'noodle restaurants or noodle stands'?
Q1. Sometimes. Usually people buy the food they want at a snack bar and then either stand nearby or go and find a table or a bench or a park and eat there.
Q2. Sometimes. You can also find sandwiches for sale in coffee shops, vending machines, and grocery stores' deli departments.
Q3. Most noodle shops are in the largest cities, sometimes where there is a Chinatown or Japantown or Koreatown. Are you familiar with those terms? When I lived near Los Angeles or San Francisco, my family and friends liked to go into one of these areas of the city and find good specialty food like what you have named. =)