Curate, connect, and discover
Personally I think it's a self thing like I said in the last paragraph. The deans proved that they have quite the power however they aren't actually all knowing, like how they didn't know Annabel had the pendulum and they don't know if Annabel's idea to make the pendulum only respond to her by tying a lock of hair to it would work.
And they too don't know why Annabel is so attached and lenore isn't as prove by them quoting they should've went after lenore because her loyalty is far from unbreakable
I plan on making another mini post that's basically a record of everything we know about the deans from s1
About their memories. Annabel lee isn't just going backwards and lenore forward; Annabel is remembering faster and more compared to lenore
Moreover Annabel remembers the trivial memories, the supposedly less important ones.
For example Lenore would remembers Annabel's first and last visits while Annabel would remember lenore showing up as Leo and a casual picnic together.
So basically lenore remembers being inlove with Annabel while Annabel remembers falling inlove with Lenore.
It's why Annabel is so hopelessly devoted and lenore isn't. Lenore remembers Annabel saying she wants her to have a better life even if she(Annabel) is forced into needlepoint. Annabel remembers the why
As much as I hate saying it; I think this is all because Annabel was more attached in life, that she loved lenore more than lenore loved her and it carried into Nevermore.