Not much to add but some things of interest:
The day seemed a trifle cold for ball playing, and the spectators buttoned up in overcoats, shivered in their seats when time was called...The seats in the grand stand were all occupied and the line of benches to the left and right were nearly filled. The crowd was estimated at 10,000. The grounds were in splendid condition....[In the fifth,] O'Neil took first on balls deliberately pitched by Clarkson...[In the sixth,] O'Neil went to first on balls...
-The Daily Inter Ocean, October 22, 1886
Another game another variety of sources disagreeing on the attendance. It's not all that important but I do find it amusing. The important point is that there was a large crowd at the ballpark for game four.