Why do some three colleges and universities need to compile their careers when recruiting teachers? Aren't all three colleges independent and private?

The three books you mentioned may not be independent colleges, but secondary colleges, that is, the education departments of special parent schools, which are managed by parent schools, but the relevant levels are different. For example, the Engineering College of Zhengzhou University is an independent college of Zhengzhou University. The School of Engineering of Zheng Da University is led and managed by Zheng Da University, but its majors are enrolled in three batches of undergraduates (the general majors of Zheng Da University are a batch of undergraduates), which is not in the same place as the main campus of Zheng Da University.