I voted for Vander, and now I'm more convinced. He's the only one who will give a permanent bonus to the deck without being played. (And keep in mind, that with an early Knight you could quite possibly draw Knight/Estate or Knight/copper, forcing a dead Knight.) That is a huge plus in my books. The next two are Anna and Natalie. Both of them give a permanent bonus to the deck after a single play. Michael comes close behind thanks to allowing a single play to hurt opponents significantly. Since such a play will likely come in the early game, it will be quite devastating. Then, the next 5 are in the same camp. They require other infrastructure to use effectively and can't work with just a single play. Bailey won't hurt your deck, so why not have him? Molly can probably find work quite quickly and Sylvia will just do her thing with minimal collision chance. Destry will work OK for either an engine or a BM deck and is pretty good. Martin provides the least useful infrastructure and will need quite an engine around a card which can be spitefully trashed by an opponent choosing to sacrifice their own Knight (eg, Vander). However, his cost of $4 helps him by making him a powerful (and swingy) opening. Last is Josephine. You have to be very careful playing her in the late game or anytime if your opponent has Vander. I would not hesitate to sacrifice a card I likely wouldn't play again in order to rob my opponent of 2 VP in a tight, late game. And, Vander just makes it more appealing.
So, here is my list:
1. Vander
2. Anna
3. Natalie
4. Michael
5. Bailey
6. Martin
7. Sylvia
8. Destry
9. Molly
10. Josephine