After a long and frustrating few weeks of trying to achieve 1850 on either my warlock on my priest, I managed to do it! I didn't have to compromise my goal of doing it with my paladin friend either! My paladin friend was starting to hate the game because of how much trouble paladins have in the small arena brackets but we busted out paladin/priest/warrior and managed to achieve 1850 and earn her paladin and my priest our season 3 weapons!
Paladin/priest/warrior is remarkably strong vs a lot of popular compositions, which led to our success. Like we beat the popular rogue/mage/priest lineup very consistently and fair decently well vs druid teams.
Now I need to see if I can manage 1850 on my warlock with my paladin friend because we're inseparable. ;)