Selenium WebDriver Safari (11.0) TypeError: Value is not a sequence
Safari provides native support for the WebDriver API starting Safari 10. Source: https://webkit.org/blog/6900/webdriver-support-in-safari-10/. Safari 11 uses the same native Safari toolkit for supporting automation using Selenium and no longer needs the WebDriver extension. This option can be enabled for Safari 11 from Develop > Allow Remote Automation.
The errors you highlighted are due to the WebDriver extension and it should be removed/disabled when running Selenium tests on Safari 11. You should connect with their support team and check if they provide an additional capability to disable this.