Since Baxter came up during the Molesley examination, let’s discuss her. She’s the one who eventually becomes Cora’s lady’s maid after O’Brien leaves. Thomas recommends her for the job; in exchange he holds her hostage. He wants to know the gossip upstairs and he’ll reveal her secret if she won’t dish.
And what is her secret? In a previous household she was convinced by an unscrupulous man to steal her employer’s jewelry. She served time and he went away free.
So, Baxter is malleable. She’s no Eight, One, or Three. She’s genuinely kind to others, even Thomas. This is a character with no Envy, so not a Two or Four. Because of her romantic feelings with Molesley, let’s rule out a Six (his Enneagram).
Five, Seven, or Nine? I want to say Nine. First of all, I like it as a companion number to Molesley. Also, I think the conflict inherent in Baxter’s crime is what torments her the most. Of course she’s embarrassed to confess to Cora, but upsetting the household balance, of putting Cora in the difficult position of deciding her fate, is more offensive to her. Molesley’s support — I would say his moral clarity, which is a source of peace for him — lends Baxter strength. Her past is not a drama for him, which makes it less of a drama for her.