What if Engelbert Dollfuss avoided assassination in 1934 and there was continued persecution of Austrian Nazis?
I don't see why it makes any difference whether Austria is ruled by Dollfuss or his lieutenant and fellow Christian-Social politician Schuschnigg. The key to preventing a German takeover is Mussolini, and the same considerations that led Mussolini to abandon Austria and seek reconciliation with Hitler in OTL (e.g., Ethiopia, the Spanish Civil War, Germany's rearmament and occupation of the Rhineland and the feeble western response to it, etc.) would exist whether Dollfuss or Schuschnigg led Austria. Schuschnigg was neither more nor less anti-Nazi than Dollfuss. If he tried to appease them, it was because Mussolini from mid-1936 cast his lot with Hitler (for the reasons I went into above) and advised Schuschnigg to seek a modus vivendi with Germany. The same thing would have happened with Dollfuss.