Nice observations. But you also forgot the finalist with five years between their first appearance. I imagine that Lindsay was in the finals of OZ five years ago and also for wimbledon. While Mary was in the finals of roland garros also five years too. Venus won her first grand slam five years ago.
Venus is my fav, but if your logic is correct, she would lose in the finals of the USopen to Serena.
When I think of life, sometimes my response is "Oh Damn!". But I still think of life anyway, "Oh Damn!!!"