8 - Is there a drush command to reset a module's config back to install defaults? I'm working on a custom module in Drupal 8 and have nested the config a bit, but getting errors and want to just reset the config for that module completely.
I guess it doesn't provide drush integration yet, but have a look at https://www.drupal.org/project/config_update

It provides a UI to compare and revert configuration with the defaults provided by a module.