Tim,
I found the faq that covers the Forbidden Lore, Its says that you chose the power and gain access to all the spells from that lore. This is in place of the normal rolling for spells, this allows you to take lores that you could not otherwise take and in addition you just know all six spells. That is why they give knowing all the spells in the lore of Vampires as an example. It wouldn't make any sense to pick the lore of Vampires and forfeit you rolling for other spells.