You don't need to delete the styles from each file individually. You will have one document which will be set as the master in your book (usually the first document by default). If you delete the styles from the master document and then synchronize styles across the book it will update the other files.
As far as renaming goes, you will have to do this either manually or by scripting.
You want to create an InDesign book file with each chapter part of the book file. You set one chapter as the Style Source. Then you choose synchronize styles from the book panel menu. Details here: