Awesome write-up - thanks for sharing!
Been missing ED stories, so this was a nice surprise to see, esp with all the Alpine driving.
I did Stelvio during my M2 ED trip in Oct 2017 and got hooked on Alpine passes. Rented an M2 Comp in June 2019 and did Grossglockner. Sadly, I suffered the same fate as you with Gotthard/Furka/Grimsel/Susten being closed when I came through - and I was there a few weeks later too (June 6).
I did hit Klausen on the way.
I'm planning another ED trip for next year (obviously not a BMW...) - aiming for July or Aug to make sure all the passes are open this time. I have 14 on my itinerary at the moment, but you gave me a few more passes to consider adding.
PS - I need to move to Germany so I can join trips like this!