One of the best reportages about the city of my youth, and after 50 years in Canada, again my place of residence since 2011. I am particularly impressed by your admiration of the Hundertwasserhaus. He is one of my favorite artists. A short walking distance from there is the Kunsthaus Wien - you may have missed it. Back in 2013, at the the Cafe Friedlich in the Kunsthaus Wien I attended the wildest Birthday Party ever of my friend @carolineschell. Another place worth seeing is the Heizkraftwerk Spittelau - my Flickr Album.
Also, you featured the Anker Uhr: were you there at 12 Noon? Then you can see a display of 12 figures rotating, with music.