Engelbert Dolfuss survives and is part of a massive dogpile on Germany. Italy, Austria, France, Belgium, Poland, and Czechoslovakia decide that the time is still good and grab what they can off Germany.
With the Nazi party defeated and thoroughly discredited, Dolfuss pressures Hungary into annexation. The Soviets fund a Yugoslav Civil War, similar to the Spanish one IOTL, and the Austro-Hungarians under Dolfuss grab up as much of it as they can. Mussolini grabs parts of Southern Yugoslavia, calling it the Province of Illyria.
Anything plausible here?
No, but neither is my idea.
I thought of a 1938-situation as well. Benes sees that an Anschluss will bring the CSR into an impossible situation. Instead he decided that an offer has to be made to Austria and to gamble on loyalty of the "Sudetendeutsche" to anything connected with Vienna.
He offers Schuschnigg the establishment of a Danubian federation with Pressburg/Bratislava as common capital and Schuschnigg as provisory Prime Minister. Schuschnigg grabs the possibility with both hands in order to be the Phoenix of Austria instead of the guy who had to surrender to the Nazis. They quickly sketch a first draft for a federal constitution.
Jansa directly flies to Prague to coordinate his defensive plans with the CSR-general staff.
Hitler is caught by surprise. He orders the (rather unready) Wehrmacht to attack. They are stopped shortly before even reaching Linz. France threatens mobilization if there is no ceasefire in order to hold an international conference. Moscow makes clear towards Poland that it would adhere to its alliance with Prague in case of a Polish intervention on Hitler's side.
Mussolini stays confused and decides to wait what happens. Hungary turns out to be Germany's only ally, but triggers a Romanian intervention. They prove to be little irritation to the Danubian forces and get overwhelmed on their own Eastern front.
After four weeks of war, the Germans are still stuck 20km east of Linz, although controlling most of Tyrolia and Salzburg. Czech forces accomplished some limited counterattacks in Saxony and Silesia. Hungary is in the process of collapsing. France finally mobilizes at least partially, same goes for the United Kingdom. Both again call for an international conference, Mussolini offers to host.
The next day Poland issues a 24h-ultimatum to Berlin that "Germany should refrain all its present or future rights concerning the Mandate of Danzig". Apparently, Poland has moved her best forces into the vicinity of the city.
Two hours before the ultimatum runs out, Hitler is arrested during a coup of the Wehrmacht. Martial law is declared in Germany by "Reichsverweser" Ludwig Beck. Beck announces that Germany is ready to accept an immediate cease-fire.
The conference in Rome starts 8 days later and restores status-quo borders but confirms the Danubian federation.
In 1939, the economically devastated Hungary offers to join the federation if monarchy is to be restored. Pressburg accepts the offer and vows not to question Romania's borders.
In 1943, Civil War breaks out in Yugoslavia. Slovenia and Croatia break free. Italy heavily supports the Croats which reach independance, but are disappointed due to the Italian annexation of large parts of the Adriatic coast (also, Italy annexes the Kosovo and establishes a puppet regime in Montenegro). Slovenia and Croatia develop close ties to the federation, but do not join outright.
In 1956, Mussolini dies. Italy returns to democracy, but a coup by fascist officers throws the country into a franchise of the Spanish Civil War. Danubian troops move into Südtirol and Triest, and, after a referendum, restore the 1914 Italian-Austria border.
A few years later, the Alien Space Bats leave Earth.