Due to the nature of this being a reverse-engineer of TurbTastic's original Mongoose Sumo map, when I made each of my three versions of Sumo I broke the scripting that maintained the score so Team Sumo wouldn't work.
After spending a few hours trying different fixes, I just said screw it and added a Stronghold to the map and made a new game variant to let teamplay work that way. So in order to play TEAM Sumo, bookmark this gametype as well....