The righty alternative to Lester is who, Alec Mills?
Would not be excited about that. Think Lester is better choice.
Regarding Marlins vs. righties or lefties, keep in mind it was a short season. For example, Tigers had a .400 BABIP against lefties and, therefore, had a wRC+ against lefties of 142. Doubt Tigers are that good but you can get that in 60 games.
Marlins had a wRC+ against lefties of 111. That was #6 in NL. Good but would not call that crushing lefties. Also, was partially because of a better than average .318 BABIP vs. lefties, so maybe just a bit lucky. Marlins have very good slugging % against lefties but they love to run against righties (and not much against lefties) and runs scored against lefties (absent the running game) is not what you’d think if just focused on slugging. OBP virtually identical vs. lefties or righties.
Don’t see much of anything here that would cause me to opt for Mills over Lester. Hope it works out successfully if there is a game 3.