Have plenty of life to spend
Personally, I see less than 10 real stinkers, with Tasigur, Lavaclaw, Wildwood, and Balefire being the real stand out failures, but the real question here is how much middling promos like Ulamog or Creeping Tar Pit will end up at, and how much the true maniacs like Liliana of the Veil will drag the mean upwards
If we can have multiple ways to win and not tutor for one combo but rather just play Magic until the deck assembles for us a combination of cards that we can use to get enough advantage to kill them, thats 75%
Counters doublers like Doubling Season work exactly the same with lore counters as with any other type of counter: You put twice as many as you'd have otherwise put
Infect is an ability that transforms damage against a player into poison counters
Notably, her first ability allows her to draw a card on other players' turns while also potentially dealing damage on other players' turns if she casts a spell outside of her own turn