I doubt there will ever be one flag because it isn’t built into the game.
As for doubles and snipers being ranks we’ll have to wait and see because they haven’t released that info yet. We do know that doubles will be a permanent playlist.
Team doubles will be a playlist on February 4, a Competitive 4v4 playlist comes mid February, TU and the Majestic map pack comes late February, And the CSR (Competitive Skill Rank)would arrive at April 1. Griffball is coming Monday