One aspect of playoff bullpen usage that isn't considered as much in the regular season is seeing pitchers multiple times. It's a topic brought up on podcasts and other discussions about playoff baseball.
In the regular season, a reliever might typically face the same team twice in a three game series, maybe three times in a four game series. The question arises whether seeing a reliever with frequency in a five game or seven game series might give batters just a little bit more of an advantage than typical in the regular season. How much of an advantage is unknown, likely dependent on the skills of both the batter and pitcher.
If any advantage is gained by seeing pitchers multiple times, then not showing any of their top tier relievers in Game 1 might have been beneficial--even slightly--to the Cubs. The Brewers gave the Cubs a look at Ashby for just one batter in the 6th (Crow-Armstrong) and the 7th (Swanson, Shaw, Busch) and Koenig for the 8th (Hoerner, Tucker, Suzuki, Happ). That wasn't much, but could the game have been finished without bringing in any of the Brewers "A Bullpen"? Maybe it won't amount to anything, but the thought crossed my mind.