You're better than me to find this solution.
The last things that would be very cool (and more clean i think) would be :
- to show the sentence and the link to the english page only if it exists
- to dynamically change the name for capabilities (by a subst) from the langage form to the english form (Capacités/moodle/role:manage in french to Capabilities/moodle/role:manage)
Going in holidays tomorrow, so i won't be able to help for that before a while...