"Groundfighting kata" sounds a lot like BJJ "flow drills" where you start in a position like the mount or guard and then transition from one position to the next by either passing your opponent's guard or using pressure and leverage to move from say a mount to a scarf hold. These are good drills for teaching you the basic BJJ positions. Check out Dave Meyer and John Will's BJJ books and DVDs, they include some of these flow drills.