Yes! It’s all up to you. We will provide you with the host company's information as part of the application process, and you will have an online interview with the management before you accept an offer.
No. Having some knowledge of Chinese can always help but it is certainly not a requirement. All of our host companies have English-speaking personnel. If you are placed in an international company, most of the people in the office will speak English
Sometimes this is the case. We have had a few instances in which the company found the intern very suitable and invited them to join the staff permanently. This all depends on your motivation and work ethic. If your host is very satisfied with your performance, it could open many doors for your future.