Am I the only one that thinks the inconsistency in the selection of leaders here is weird; Victoria is selected because, in spite of not ever having any real power, she was the figurehead of the British empire, whilst Catherine de' Medicis is selected because, in spite of nominally having no power, she in fact held real power behind the scenes. It shows that there is no particular set rules for selecting rulers for Civ VI; instead, Firaxis is doing everything it can to ensure they fill a female quota. With this level of leniency with selecting rulers, it would be quite easy for them to have achieved a gender balance by having one male leader and one female leader for each civilisation.
Also, am I not the only one who would rather that Isabella of Castile was swapped for Phillip II than Catherine the Great was swapped for Peter the Great? Catherine was among Russia's most powerful imperial rulers, but in the case of Isabella, the same cannot be said of her standing in Spanish history when compared to other Spanish rulers; Spain had no colonial empire in her time, just around 600,000 kilometers squared of land in the kingdoms of Castile and Aragon, and yet the Spanish empire would go on to rule near 20 million square kilometers.