The cc I made is corrupted as in the picture

Hi. If you were to assign this template to the nude bottom, you will see that it goes outside of the "for bottom area". Since your garment does not cover the bottom by much, you need to keep its uvs in mind as well.

- expand rig, make bottom selectable;
- select bottom, shift-select your garment;
- in uv editor select everything and remove any image in the background by clicking on x button next to it(both items must have the same image in the background unless you are using 2.79+);
- View - Draw other objects;
- now you will see the uvs of the bottom in the background;
- you should delete more of the body from the back, it is covered by clothing and only occupies the uv space;
- and do not scale the uv islands individually unless the difference in quality is acceptable. The geometry that covers the hole can be smaller than it should be, the uvs of the front of the garment should not be bigger than that of the bottom