Unlikely.
I stated my opionion regarding the Kanton Übrig at a different place - it boils down that even disregarding all other factors, Swiss internal politics make it very unlikely.
While there were publications at the time that disagreed (I read one from 1923 - I'd have to look it up again however, I don't remember the title), the most common problem that was stated against the (German-)Austrian nation was that it was too small to be economical viable. So anyone trying to set up even smaller subdivisions it pretty much damned to fail.
While I never studied the Salzburg situation in detail, with Tyrol it was a desperate attempt to keep the historical country together. I'd have to look it up again, but IIRC the 98% vote wasn't in any way representative.
What did happen was, that for Tyrolean politicans the most important thing was keeping the area together. IIRC they didn't (stopped?) sending representatives to Vienna when it became clear that Austria as it was wouldn't be able to stand up to the Winning Power Italy over South Tyrol. They hoped that the more powerful Germany would be able to create facts on the ground as it is, forcing Italy to abbandon their claims by force... Pretty unrealistic if viewed with nowadays, or even 1930s knowledge.
The probem isn't the descisions by the Bundesländer - you have to make others accept it. Germany isn't really in a position to do anything between internal conflict, having parts of their country occupied and the economic situation (inflation...).
Vienna wasn't about to let any parts split off - especially losing Salzburg would probably be interpreted as a death sentence to Austria.
The Entente, and more so Italy, also weren't about to let it happen. The most sympathic would probably have been the USA. And they were already swinging back from intervention in Europe, they didn't even ratify the treaties all this is based on.