Occasionally some decks will require more, while some formats (or deck archetypes) feature enough mana acceleration and cheap spells that they require less
On the other hand, if a spell or ability deals lethal damage to a creature enchanted with an Aura that has umbra armor, the game rules regarding lethal damage cause the Aura to be destroyed, not that spell or ability
Five life for a token, a card, and a treasure
Her heroic trigger will toss a +1/+1 counter here and then you can tap her to remove one to draw a card, for no mana down, just pure card draw
You can find my other precon upgrades here: Ahoy Mateys is a Blue / Black / Red Pirate deck: the goal of the deck is cast a bunch of pirates and go attacking, looting your opponents for treasure (Malcolm, Keen-Eyed Navigator), stealing their cards (Ramirez DePietro, Pillager), and even their permanents (Admiral Beckett Brass)