I need to remove / add new attributes to one of my record type, but container is deployed to production yet. Any chance?
As you can see - I hovered over the X button my mouse - it not possible to remove attributes.
You should be able to just make modifications to the development container and then deploy that again to production. See the documentation: https://developer.apple.com/library/ios/documentation/General/Conceptual/iCloudDesignGuide/DesigningforCloudKit/DesigningforCloudKit.html
It says: Prior to deploying your app, you migrate your schema and data to the production environment using CloudKit Dashboard. When running against the production environment, the server prevents your app from changing the schema programmatically. You can still make changes with CloudKit Dashboard but attempts to add fields to a record in the production environment result in errors.
Then see the part 'Future Proofing Your Records'