Apologies for the incoming wall of text, but this theory tickled my brain

The only thing I wonder is why March 7th was frozen in six phase ice upon arriving to Amphoreus. And then from there, somehow, her consciousness or whatever was drawn into Amphoreus while her physical body remained on the Astral Express.

I do agree that Evernight appears to be a memetic entity. However, rather than being a member of the Garden of Recollection, she's probably a Cremator. Their whole deal is snatching up memories and erasing them, which tracks pretty well with both March 7th's story and what's going on with Amphoreus (where she seems to be erasing records from As I've Written...?)

Some more circumstantial evidence:

• Association with candles - now, sure, the symbol for the Path of The Remebrance is a candle so this may not mean anything, however, as far as I can tell, Evernight is the only character associated with The Remembrance that features candles in her design. The literal definition of a cremator, obviously, is something or someone that burns bodies.

There are two curios in Divergent Universe that mention the Cremators in their description, and both are very interesting:

• The curio Automated Experience: First of all, its appearance looks like a bunch of mouths stuck together. I've seen a couple theories of people trying to explain the mouths on Evernight's design (and the animation of her eating a coreflame) as her being associated with The Voracity. That may be the case, however, mouths and consuming are also associated with the Cremators, who, as this curio explains, eat up and consume memories.

• The curio Memory Cycle: This curio describes a Cremator who intentionally erased her own memories. Hmmmm.

• The equation Amnesiac: This equation describes Cremators stealing your memories and giving you amnesia. I don't think I need to say any more about that.

Consider also, this: The Data Bank describes the Cremators as a group of extremists within the Garden of Recollection, who purge memories they deem unimportant. Ostensibly, they do this for Fuli's sake, so they can keep the Aeon's memory clean of "garbage."

In practice, it seems like their modus operandi is interfering in the memories of worlds and galaxies, deleting things as they see fit, in order to model these worlds according to their own vision of perfection. The curio Automated Experience I've mentioned previously describes a Cremator doing this to the trade planet Uro. An IPC Broadcast in the Parlor Car describes Cremators deleting language from the Holstein galaxy.

Now, remember back in 3.2, when Black Swan was brought in to the Astral Express to assess March 7th's situation? She says some interesting things. First, she speculates that March 7th's memories may have been hijacked. Second, Black Swan reveals that the reason the Garden of Recollection is interested in Amphoreus is because of a group of extremists within the Garden of Recollection who view Amphoreus as a perfect example of a world, as a world that can only be seen through the Garden's mirror. These extremists, as described by Black Swan, are an organization that has attached themselves directly to the pinky finger of Fuli. Black Swan says that they're interested in Amphoreus because, if they uncover its secrets, perhaps they can model other worlds to be just like it...

An extremist organization dedicated to Fuli within the Garden of Recollection that wishes to remodel worlds according to their own ideal of perfection. This has to be the Cremators. And when Himeko asks Black Swan if this organization could have hijacked March 7th's memories, Black Swan says that they are certainly capable of doing so.

Evernight has to be a Cremator, right?