Drush is the ultimate tool and companion for Drupal and it does a great job in situations where we want to import or export our Drupal database.
Everything was going well with your Drupal setup on local and then GIT STRICKS BACK. You are trying to do a git checkout and moving to a different branch but now you have an error of GIT not able to unlink file and a modified file.
While working on Drupal 8 one of the issues you might face is you won't get "Register" link for anonymous user. Here are two simple ways on how to hide "Register" link for users with administrator role.