Is there a way to use Translation Overview with Entity Translation?
Maybe you should consider switching from the Translation Overview module to the Translation Management Tool module, which allows all Drupal text elements to be used as source for translation. I.e. Nodes, Entities, I18n Strings (Menu, Terms etc.).

That's also what seems to comply with what is written on the Translation Overview project page, i.e.:


  ... The superseding Translation management (TMGMT) module was initiated with Drupal 7 and is already well ported to Drupal 8. We highly recommend it - already with Drupal 7.