It appears that the fact that Saga is a reincarnation of April is pretty much confirmed throughout the game, and we are lead to believe that April in some way is saved through this reincarnation (I prefer this term instead of saying "reborn", as Saga is definitely not just an April 2.0). I know that there are a lot of differing options on this resolution of April's story, personally, I like the concept in itself, and I think Saga's scenes were done beautifully, but some aspects are still bothering me. (They are actually bothering me much more now, that I had some time after completing Chapters to reflect on the whole story, initially upon finishing it, I felt more satisfied in that regard.) I basically have two large issues, one plot- and one character-related:
1. After all the attention it got in Dreamfall - it was basically the #2 main motivation for Zoe besides finding Reza - what the heck did Zoe actually do/achieve/contribute to save April Ryan, i.e. to lead to reincarnation of April as Saga? I think we are meant to "feel" this, there are many plotpoints in DFC that are not spelled out explicitly but can be "grasped", but it's much less clear with this particular side of the story...
2. In TLJ games, when they are at their best, the magical and supernatural journeys the characters go through reinforce and parallel their inner journeys, and I think most of us would agree that this plays quite a large role in the way many of us have a strong emotional resonance with these games. There is a lot that can be "taken" from the core stories of April, Zoe and Kian that is relevant to the everyday life. But my issue is, what is the "message" of April being saved through death? (no offense to those whose religion it is a part of, but reincarnation can hardly be applied to the everyday player's life) It's not that Dreamfall should be a "how to live your life"-guide of course, neither do I think that April's abrupt death was a bad storytelling decision. It certainly avoids a trope, and it could have led to some great investigation about the inevitability and acceptance of death, about feeling aimless in life, or whether death can truly mean being saved in some cases - but we didn't really get any of that. April being saved through dying, even with all the sadness the characters express multiple times about their loss, is presented almost as a clear success - and frankly, that is a bit disturbing.
I would be glad to hear your thoughts about these, this forum has helped me a lot with getting my thoughts sorted out with the ending. (and they are positive overall, by the way) For a start, I tried to think of the possible theories (some more prevalent, some not so much) about Zoe's role in saving April, but unfortunately, none of them seem very convincing to me.
Zoe influences events so that they lead to April's death:
This might be the most convenient theory, but I just can't buy it. Zoe played hardly an influencing role in the events that led to April's death in the swamp. If Zoe hadn't been there, everything would have played out almost exactly the same, with the exception of maybe Kian meeting Zoe (see below), it's very hard to argue that Zoe was the "nudge" that was needed. Also, April was suicidal anyway already, she was chastised by her friends (especially Benrime, if I remember correctly), for behaving carelessly on dangerous missions, so it doesn't make any sense to me to organize a plot involving Zoe just to get her killed sooner... Also, what I mentioned above concerning the implications of this storyline being a bit disturbing, I feel is the most apparent in this case.
Zoe somehow used her dreaming powers to save her:
This would definitely be cool, and it might be supported by the fact that the White Dragon sent to Zoe specifically to the swamp, to witness April's death. She didn't actually do there anything at all, but maybe just being there passively enabled April's/Saga's rebirth. It might also be supported by the "white lady" comment of Faith. Unfortunately though, it is never implied at all that Zoe would possess such powers, or that her Dreaming/Storytime-related abilities would have a connection with the White Dragon's hard-to-grasp reincarnation stuff. Whenever she uses her powers, she does so actively, and since her abilities got quite a lot of development in DFC, it probably would have come up if she had such reincarnating abilities.
The reincarnation was not a given, April had to have the will to "stay alive", and Zoe convinced her:
If I had to choose one to believe, I would pick this one. Maybe, the reincarnation did not happen "automatically", but it was important that April, deep down, despite her deathwish and lack of direction, still had some urge in herself to continue. And maybe, it was Zoe's attempts to shake up April that led to this in a subconscious way. This still doesn't explain why Zoe had to be present at the swamp, and there isn't anything that states that this reincarnation depends on the thoughts of the person dying (though there isn't anything to the contrary either) but it is, I think, relatable on a character level. April's death and reincarnation could be interpreted as a spiritual death and rebirth in that way, which is in line with the spirit of these games, and personally, I would be content with it. But there isn't really evidence. (which doesn't stop me from making this my headcanon )
Zoe's involmement led to Kian meeting April, which led to Kian becoming the kind of person he became at the end of DFC, which led to Saga becoming a better person overall:
I only included this because it seems that Kian and April's meeting was the only direct and obvious consequence of Zoe's involvement. But it's hard to make a connenction from that to Saga and the reincarnation, and Saga seemed like she was already "whole" before meeting Kian. So, I think this is pretty far-fetched.
These are what I could come up with, feel free to expand!