Don't know too much about 18th century Russia, but I was wondering about the possibility/probability of a longer reign for Ivan VI. There were plans in the works to marry Yelizaveta Petrovna to Anton Ulrich's brother, Ludwig of Brunswick. This wouldve sent Lizzie out of Russia.
However this plan was scuttled when Lizzie decided on being empress herself. Ludwig ended as sometime regent of the Netherlands, but wouldve become duke of Courland as dowry.
So what if Lizzie and Ludwig had married, and Ivan VI gets a full lifespan and reign as Czar. What would the effects be?