What do you think are the reasoning loopholes in Chinatown Detective 2?

First of all, this is a very good comedy movie. But look carefully, there are indeed some reasoning loopholes. Here are some points.

1. How did Qin Feng pass two crime scenes at the beginning (one of which is still fake) and then introduce a fake murderer Yi Song's cell …

How did three wanted men borrow books from the library?

3. Why is Lou Guo Fu in the same hospital as the other four victims?

4. Why is there sugar at the crime scene? Shouldn't that doctor only go to the sugar factory when he kills the fourth person? Or an abandoned sugar factory? When I saw how the three of them finally escaped from prison.