Since you are in the process of updating your great plugin, let me give you another improvement wish. We're working on a multilingual Moodle installation and therefore work with multilang filters a lot. We see something not affected by filters in scheduler. In datelist.php for example, course shortname (and location, too, probably). It shouldn't be a great deal of calling format_string and having the filter applied.
I attach a screenshot for you. What you see is the multilang2 filter syntax.
It would mean a lot to us if you could implement this. If you prefer, I could also prepare a Pull Request for you.