I updated my Feedback-version to your latest provided version and after submitting a Feedback by my test student, it was really anonymous (mail from administrator with anonymous Feedback entry notice).
The language issue looks very well. There are only 2 small things to fix:
- in edit mode: first menu point "Overview" missing German translation
- in edit mode - menu "Einträge anzeigen": button text shows not correct German "ä", instead I see "Einträge anzeigen". Maybe it has to be encoded in unicode.