Thank you! I've hacked an implementation for now that just guesses the ranks on the client side without grabbing the actual ranks. The players will only discover it if they're playing sitting side by side.

You can get the current players rank when calling GetGlobalLeaderboardView, etc but you can't get the rankings of your friends. GetSocialLeaderboard only returns your friends and their scores but not their global rank. I would like to be able to show the global leaderboard and the social leaderboard combined as one single leaderboard in my app and knowing the friends global ranking would allow me to do this.

I implemented this pretty easily just using events. Instead of adding a friend I instead send a 'friendRequest' event to the potential friend. once that player views the event and accepts the request the friends are added.