To make long story short, the numbers are as follows:
Killed in Action: 6305
The missing are presumably deserters, prisoners taken by Novorossia, or soldiers who were killed but whose remains were either not recovered or not identified. The low number of wounded soldiers seems odd, but it may be the number of severely enough wounded to require hospitalization and/or evacuation. Light wounds could be treated by brigade medical personnel without the casualty becoming officially or unofficially reported, and the soldiers themselves may be concealing their wounds from own parents so as not to inflict additional stress on them.