Ok, so a War of Polish Succession is likely to occur prior to having Francois made King?
The War of the Lublin Confederation & The Polish interregnum
1730 would bring disaster for Austria. In Italy, the Spanish would be successful in the siege of Gaeta in April, and would decisively defeat them in the battle of Bitonto a month later. In the north, the Franco-Sardinian forces would conquer Parma, and were ready to invade Tuscany. The Duc de Berwick had driven the Austrians back to Mainz, and had besieged the fortress.
For Austria, their endeavor in Poland was no longer important after being dealt with such losses, especially with being unable to secure more allies. Also, with the death of Augustus II in June, and Franciszek dying in February after slipping down the steps while leaving Mass and breaking his neck (which was heavily satirized by the Szlachta and Austrians, immortalized with the epithet Głupi Francizek or Franciszek the Stupid), both sides were without a king. Austria had announced Augustus III as the true King, while France had dubiously announced that Francizek's grandson was the true heir as Ludwik II. Austria would decide to sue for a separate peace, leaving Russia as the sole supporter of the Saxon pretender.