Houjou Souun will already have disappeared if you pick this bonus pack.
If the Kenshin IF route is taken, Mouri Motonari will be disqualified from the Emperor Race. It is still possible to get Kikkawa Kiku's character clear, by getting her to Trust before defeating the Mouri-less Mouri House. Mouri Motonari MUST NOT BE CLEARED to see the event with unlocks the bonus. If the Kenshin IF route is taken, Baba Shouen will be disqualified from the Emperor Race. Sending all four of them to fight in the same battle will trigger an event, save after watching it. Picking a Family Bonus gives you the characters of the listed House, but you'll start the game with that House hostile.