The functions of the following stores may not be considered in the design. If it is changed into a hotel or restaurant, a flue should be added to the roof, otherwise the hotel will not pass the acceptance.

There is no way. It is difficult to define whether there is cheating on consumers. Most houses with shops on the ground floor have this problem. You can consult the Consumers Association.

As long as there is no gap in the pipe cavity, the oil fume will not penetrate into the wall.

Because you are located near the roof, there may be some odor due to the wind direction when you open the window for ventilation.