The data that the current replay API can obtain is very limited. We can’t even know which side won unless we play the replay and use visual recognition or manually record the winning side.
Or maybe there are reverse engineers in our community who can parse the replay files (unlikely)
in conclusion:
Please add more property to the replay json to make statistics easier (Winning faction, timestamps when players entered/exited the game, scores etc.) . This will show your determination to be transparent about game matchmaking.