It's the Long Way Around

Okay first I wanna show the evidence that is fairly easy to point out. To be honest these things alone I feel are enough evidence, though it's far from the only evidence.

First is the lineup from the fakeout ending:

In the fakeout ending, when the scene shows the lineups of all the versions of Elster, and also the versions of Ariane, Falke can be seen at the front of both.

All the way on left here.

And all the way on the right here.

And if she is at the front of the Elster lineup because she has Elster's memories, then she most likely is at the front of the Ariane lineup for the same reason.

Next is Falke's intro screen prior to her boss fight:

This one is also relatively known though I feel like it gets treated more like trivia or goes relatively forgotten after people learn it. This being that when Falke's face is shown up close right before her fight is the same as Ariane's from when she's shown up close in the endings.

It is worth noting that FKLR units in truth don't actually bear any resemblance to Ariane, but here Falke is a nearly one for one match. A very reasonable explanation for this is Elster herself, she is being shown awakening because that is what Elster is seeing. She is recognizing the Ariane within Falke, or recognizing that Falke is becoming Ariane.

Or even another alternative explanation could be bioresonance, a power able to shape reality, is literally molding Falke physically into who she has started to or has become mentally.

This detail overall is extra interesting when you consider Falke is corrupted, she has degraded physically in a similar way to all the other Replikas. Yet she is still shown looking like Ariane to both the player and Elster.

Third is what I would consider kind of obscure but still pretty well shown/known:

This relates to the position Falke has within the story. Much like Ariane she is asleep, laying in a bed rather similarly to how Ariane is laying in the cryogenic pod.

For Elster to reach Ariane she has to also reach Falke (Artifact ending is kinda different to this, you don't ever physically have to reach Falke, but you also don't physically reach Ariane either.)

If/when she awakes, it is Elster's goal to kill her. If Elster is to ever fulfill her promise to Ariane, she must also fulfill it to Falke. (I touch again on this later)

Okay with those three mentioned I wanted to talk about more of the obscure things the game does to show Falke having Ariane's memories.

First 'This God Won't Forgive You' (this is one of my favorites):

Immediately prior to fighting Falke, these words flash on screen. Which on a surface level are easy to ignore as just a way to establish murderous intent on the part of Falke, and yeah it is that, but with how deliberate everything in Signalis is, this quote kind of stands out. There's not really an obvious reason for Falke to have this kind of feeling for Elster. Elster hasn't really done anything to Falke. There would be nothing for her to forgive Elster for, but there would be for Ariane.

Elster died before she could fulfill the promise, and as evidenced by the story of Signalis existing at all, it had a big effect on Ariane. And though in the relevant ending she seems accepting of Elster returning to fulfill the promise, she still sees Elster dying first as having failed to keep it the first time.

This is further evidenced by the wording of the line, 'THIS GOD' would suggest there's another god who could forgive Elster, of course, this other god is Ariane. The wording also implies that what Falke cannot forgive is the same thing Ariane may forgive. Which as siad before is very likely the fact that Elster died first. Falke, blinded by grief and rage will not forgive Elster for dying before Ariane (or herself through memory).

Second the music:

Two parts to this section, ill keep the first short because it's pretty self explanatory, and also the second is just plain more interesting.

First is Falke's theme is Ariane's theme backwards. This is HUGE evidence, but I just simply don't have much more to add to it as far as facts go.

Second is related to the song in the OST called 'The Promise', it's essentially a remake of the middle two minutes of 'Raindrops' by Chopin. If you aren't already aware, 'Raindrops' makes its own appearance at the beginning of the game right after you take The King in Yellow for the first time, and as you see the signal begin to send, and also where the words 'Remember our promise' appear for the first time (if i am remembering correctly). That is to say the song is strongly associated with the promise between Elster and Ariane.

That makes it interesting then that 'The Promise' is the song that starts to play as you defeat Falke. In fact it's punctual to the point that the paino motif that makes its refrence to 'Raindrops' and the promise in game clear only plays the moment Falke actually falls over dead. This is done as if to suggest that Elster is fulfilling the promise in some form to Falke as she intends to do for Ariane. This is further realized though how the second instance of the 'Raindrops' motif, which is much more intense, plays as Elster begins to trek through the gate toward the Penrose 512. The song eventually concluding as she successfully enters the ship to show that the though Falke's death was to fulfill the promise to a recreation of Ariane, now is the opportunity to fulfill it for the Ariane.

Third the artifact shows when Falke is vulnerable:

The artifact, or the symbol for it is one of the most open to interpretation aspects of the game. Not much is ever explained about it, and its main role in the story is for the secret ending which is a whole can of worms on its own. Falke does have a role on both the Ariane and Elster side of this secret ending, but that isn't what I want to touch on here. Rather I want to emphasize that one of the few things that can be observed about the artifact symbol is that it always appears in relation to Ariane in some way.

Leading to Ariane's room.

On the back of The King in Yellow

Over Falke to signify her vulnerable state.

With other examples of the artifact and its symbol being used in strong connection to Ariane it being used on Falke shows how Ariane is as much a part of her as Elster is.

Unordered things that are kinda relevant/worth mentioning:

Signalis is a very deliberate game, which makes Falke's journals interesting. They do pretty explicitly mention her memories melding with Elster's, but in other places its rather intentionally vague. Lines like "We were dancing to that song they start the broadcast with. We feel asleep watching that movie we had seen before so many times. If only i could take us back to that time when we were happy. These memories are mine now." Which don't state which perspective these memories come from. Or another note which contains the line "Memories from other lives" the plural use of lives implying the memories of multiple individuals.

I also wanted to give a bit of speculation why Falke's diary and overall narrative frequently mentions her being overtaken by Elster's memories when Ariane's are also implied to be present. One possibility is that contending with memories from both was too overwhelming when two would already be too many and so she could have suppressed the memories from Ariane such that she would still be able to function after on some level, or until she went to sleep and stayed that way.

Another possibility, and my more favored one that also fits a lot of the evidence here is that it has to do with what Falke can and cannot do. With the memories of Ariane and Elster in her head Falke was immediately confronted with the fact that Ariane would not accept her as Elster and that she would be incapable of fulfilling the promise. Thus never allowing her to reach an apotheosis for the the part of her that has become Elster. What she can do, however, is mimic the role of Ariane. She can sleep, and she can wait for her beloved Elster to arrive. This is further helped along by the fact that she does not awaken to Elster's presence until Elster remembers that she is seeking out Ariane and not Alina. In this way she can achieve a form of Apotheosis for the part of her that has become Ariane. This allows her to more easily process and accept those memories as a part of herself. But her inability to do so for the memories of Elster causes her to become lost between herself and this other identity. "I’m no longer fully myself anymore, but I've not fully become someone else either." In more simple terms, she can "become" Ariane thus accepting this new part of herself and maintain her identity, but she cannot "become" Elster which leaves her lost between identities incapable of being Elster or staying as herself.