PS: Personally, don't study in China. Learning Korean directly there is very effective. 1 year, just take a TOPIK at the end of Grade 6. Level 5 is really easy.
You heard that graduation in two or four years mainly depends on majors. Four years of undergraduate course and two years of junior college, the same as in China. However, you can graduate early. The credit system in South Korea is much looser than that in domestic universities. You can take four years of credits in two years, but the focus is on professional compulsory courses. It takes four years to study in two years, not to mention enough time. It may not be possible to start a series of courses just during school hours.
3. I have been to the dormitory of the University of the Arts, which is still good, but there is still a common problem that I can't live in it. In terms of food, the school canteen is the cheapest and most nutritious choice, and it is a very standard Korean food. The class size will not be too big, about 20-40 people. As for school uniforms, each department is different, and no one asks you to wear them.