The main thing i was looking at for the Undead Lord was the additional 1/2 healing on undead creatures. Since a Dhampire is considered Undead with healing, that would benefit the way i want to run. While the Oracle of Bones gives you a servant, it doesn't give you channeling, which was the main reason for wanting to go Undead Lord. the skeleton was just a little bit of added bonus. However it would make sense for a Vampireish creature to have a minion, and that is why the skeleton would have been a good pick.
If the Pathfinder Society is suppose to be all good and noble, half of the missions involve theft, while the other half involve killing someone who has already been beaten. we don't go out and kill towns people, but then again we do have daemon's doing our bidding and we do raise the dead to do our dirty work. the only thing in the Undead Lord build that is different from that of any summoner would be the additional healing to undead creatures.