As a language learner myself during school and university, i learnt that it is not all about the entertainment value of the class. the learner may have to repeat the same thing several times before the grammar point is understood (usually through repetition until it becomes automatic),  the pronunciation is correct or the the speaker can express themselves as they wish. However, here in China it seems to be all about entertainment rather than proficiency for many students. The boredom level is quite low. Many students sit back and expect the teacher to do the work. This is not how learning a language works ! When i am learning Chinese i insist my teacher makes me repeat the sentence over and over until i get it right. If the topic is 'shopping' i will practice many conversations with variations of grammar and vocabulary. through role play, get the students to create their own scenarios. Give them the vocabulary and make the students do the work !

Before the CTs can change, they must be aware of the need to change, be willing to change, welcome change and be given the tools for change. Do not try "band-aid" solutions but put together a package that covers those points. Then, and only then, can you offer to "teach" the CTs a more communicative and interactive approach.

This is going to be difficult, as you need to train teachers (with limited English language skills) how to teach the English language to ESL students.

As you need to improve both their [the teachers] English language and teaching skills, I would suggest having activities that would incorporate both:  do a lot of guided and repetitive role-playing teaching activities. Your training module will include, but not limited to, the following:  preparing the materials, knowing what and which materials to use for certain age groups, how to use the materials effectively, explaining the goals, pacing yourself in class, and having them observe actual classes that are conducted in English.

If the headmaster insists that the Chinese teachers do the teaching, take into consideration Sinobear’s advice and incorporate that into your training module.

Assess the situation (for present and future considerations) and advise the headmaster accordingly.

Give them lessons/ games/ activities that they can use in the classroom. They will not make any change to how they teach. They will continue to do the least amount of work possible. Ineffective teachers are not fired, great teachers are not paid higher salaries. "So why should I work hard to be better?"