If you choose to draw two cards, then replace one or more of those draws with some other effect, the rest of Sylvan Library's ability still happens. If you've actually drawn only one card that turn, you must choose that card and either pay 4 life or put it on top of your library. If you haven't actually drawn any cards that turn, the rest of the ability has no effect.
Ну ты понел.
706.2 - ...The "copiable values" are the values derived from the text printed on the object (that text being name, mana cost, card type, subtype, supertype, expansion symbol, rules text, power, toughness, and/or loyalty)...