I think 500 actual users is wildly optimistic, to be honest. The number of active slack participants hasn't really changed since the game was released, and the daily volume on bittrex is trending downwards if anything. Combined with the fact that the in game leaderboard currently seems to be less than 100 strong and I think all the signs point towards far fewer than 500 active community members.

On the subject of the leaderboard, I hadn't fully appreciated that one of the top ranked names seems to share the name of the official twitter account, and as you pointed out there seems to be a few very familiar names on there. To me that just reeks of stupidity. Pre-release testers and team insiders shouldn't be allowed to take part in the competition, it gives them an unfair advantage, and more than that it'll put actual players off. Poor show.