The attendance was large, it being estimated that 16,000 witnessed the game.
-The Atchison Daily Champion, October 23, 1886
Sixteen thousand people witnessed to-day's contest.
-Bangor Daily Whig & Courier, October 23, 1886
...the crowd, estimated at 16,000...
-The Daily Inter Ocean, October 23, 1886
I think the sixteen thousand number is a mistake that began with the Inter Ocean's game account and spread to other papers. The Inter Ocean's account is, word for word, the same as that in the Tribune that I've already posted except that the Trib has the attendance at 10,000 and the Inter Ocean has it at 16,000. I think the Inter Ocean read 10,000 as 16,000 and printed that mistake. When I first saw the number in the Atchison paper, I wasn't sure if it said 16,000 or 10,000 so I can understand how this happened.
And this, of course, doesn't even address the question of whether or not there was really ten thousand people at Sportsman's Park for game five. But I'm rather comfortable saying that there sure wasn't sixteen thousand at the ballpark on October 22, 1886.