Logo is not displaying
This Link might be helpful :  http://www.lohmeyer.rocks/blog/2015/01/14/00187-print-your-themes-logo-path-drupal-8-twig.

I think you should define the logo path variable first into template.tpl in MyTheme_preprocess_page function.

One More thing you are trying to use {{logopath}} in 'span' tag and into 'src' its {{logo}}.