You could also take the gubbins out of the cig lighter adapter and just wrap it up in tape. They're usually only the size of a large stamp. That's how my fixed phone charger bracket runs in my A6
Without following all the tracks, I'd say some of the surplus lamps in your diagram are probably for switches, rather than bulbs you can get to.
Elsawin implies that the mirror has to come off before that trim will move. Its not very clear on how though - "use screwdriver to lever out interior mirror on left side between mounting plate and mirror base"