So, maybe I'm weird in this, but any time we don't get the "disembodied voice" (speech with no bubble) I'm wary of attributing what's going on to Hydaelyn. Not that I don't think she's involved at all, but it feels like it's only during "major" events that she directly acts. Awakening our Echo, setting us off to find the other Crystals, warning us of Lahabrea (twice), saving us from Ultima--these are the type of event where she seems to step in directly. As you'd put it, though, I have no evidence that she *isn't* acting at these other times; I'm just wary of defaulting to the "yes" position.
That said, where the power of the Crystals of Light is certainly. . .intertwined? with Hydaelyn's, I'd have to say that they are separate. After all, it wasn't "By thy deeds will I reveal them to thee," it was "By thy deeds shall the Crystals reveal themselves to thee." That is, the Crystals of Light appear to be distinct from Hydaelyn. As such, I'd have to say that it's the Crystal of Light's power that's ripping the Wind Crystal of Light from Garuda. Same with the Lahabrea fight. Hydaelyn's expended much of her energy just to shield us from the first Ultima cast, and she flat out tells us she can't shield us from a second. While it's possible she's mustering up enough strength to help us defeat Lahabrea, I'd sooner say it's our drawing on the Crystals.
Dunno how I forgot that. Interestingly, though, I did just rewatch that scene, and the "star shower" portion never occurs until Chasing Shadows. We don't get a vision of the past (which would be the typical sign of the Echo) until the next quest entirely. Are we certain that the conversations with Hydaelyn are even Echo-based? I always thought the consensus was that the star shower was the sign of awakening to Echo, but I could be off on that entirely.
Now to skip around a bit:
True, so I might as well address it now. There's certainly a bit of a feedback loop going on, at least inasmuch as we're using the power we've been granted to defeat what we couldn't otherwise, thus gaining even more power. That said, though, I do believe I've made a valid assumption, at least given the information we have:
And later in the quest Reclamation:Originally Posted by Hydaelyn
The crystals bear the power, but without the light shining in our hearts, we would still succumb to darkness. The Crystals grant us strength; in strength the light flourishes; the Crystals reveal themselves to the light; the loop goes on. . .Originally Posted by Hydaelyn
Also, the lines about steeling ourselves to stare into the Heart of Darkness makes me wonder if she isn't basically warning us to never give up hope, because our hope and will are all that keep ours souls alight. That's something of a derail, though.
I suppose you're right, but I'm not used to things being called anomalies if they have a known source. Hence, I took it to mean something more like, "There's something odd about your aether. Also, Hydaelyn chose you as a champion." As you said, though, it could ultimately go any number of ways.
I kinda took it to mean as one awoken to the Echo, but it could just as easily be as the Bringer of Light. Although, if I'm right about our status as the Bringer of Light depending just as much on our hope and spirit as it does on our power, that has interesting implications.
It is maddening to her, yes, but I still find it interesting that everything about the end of the cutscene says that she's been defeated entirely, that our throwing off her tempering and drawing out the Crystal of Light were just as damaging as all the fighting we did up to that point and then some. I mean, it'd be one thing if her posture were upright and she were raging; instead her posture is broken and defeated, her confidence shattered. It's not until Gaius taunts her that she again rallies. Without that, we've defeated her after she powers up by basically powering up ourselves and completely overwhelming her.
Also, you didn't really touch on whether or not it's the Echo that allows us to absorb the Crystals. Unless you mean to say that they're both ultimately coming from Hydaelyn, but I don't think the Crystals are.
I've never actually been fond of this theory. I mean, I see how it could work, and it's interesting to think about, but it leaves a bad taste in my mouth, so to speak. Just, my instincts tell me this isn't the case. I think it's that I'm willing to take the game at its word when it says that the Echo makes one immune to tempering.