I initially had looked into women in 19th century baseball through the Virginia Brights / Dixie / Sub Rosa cards, the N48 & N508 tobacco cards. It seems that these do not represent actual female players, but more likely actresses (or employees), as the same women appear in various topical scenes besides baseball.
That being said....I do think there is a direct connection between the appeal of using women in baseball-themed advertising in the 1890s (and again during the postcard era of the 1910s), and the rise and popularity of the Bloomer barnstorming teams.