No, actually, I haven't . (And, glancing and galloping through this thread, I realised that, inexplicably, I had somehow missed this post....) Evidently, another treat is in store for me...
As it happens, most of these works came to me as gifts from the German partner of one of my brothers; she loved 'Buddenbrooks' and also gave me - over a period of several years - the others as gifts.
Okay, 'Mefisto' (which I already know I will 'get', and be fascinated by, since I love that sort of story) and 'Siddharta' (which I know next to nothing about) are on my to-read & must-read list...
Because you've said you like this kind of 'infos': I just noticed that saying Erika, the wife of Gustav Gründgens, was the sister of Klaus. Well, since the actor and the author both happens to be called that way it wasn't very informative. She's the sister of Klaus Mann. There are also numerous books about the Mann dynasty as well - probably comparable with the Kennedys in the US - which are interesting to read as they, the family, combine and represent lots of important and interesting questions, styles, ideas and the changes regarding all these aspects due to the course of time and what we learn now in our history lessons
. If you're intersted I could search for one or two publications.