Yes. That's what YOU are saying.
I don't recall ever having a source on this.
The LTTP manual. The same that says the Sacred Realm has a golden sky in the first place. (A statement that doesn't exist in the Japanese manual anyway, so it's probably just a coincidence the sky is golden in the Twilight Realm, unless someone wants to argue that NoJ is taking ideas from NoA, but that's a whole new can of worms entirely.)
So it is very much "the same."
Being invaded by the same magic is not the same as being the same realm.
1) We don't know how large the Magic Mirror is. We do know that both are able to be lugged all over Hyrule, though, just like every other oversized load Link has ever had.
2) It never falls into evil hands, so we don't know if there's any danger, do we?
1) The Magic Mirror at the very least can't be as big as the Twilight Mirror, since it can fit in his pocket. The Twilight Mirror is only carried around in fragments. Fragments, might I add, that Midna carries, and she seems to have access to some sort of Hammerspace.
2) I never said anything about it falling into evil hands, just that it had an evil, corruptive power. Look what it did to Yeta. It's also presumably the source of their guardians' powers, or something, from the looks of it. Regardless, the Twilight Mirror has an outright evil power. Midna says so herself. She claims, after claiming the last piece, that it's too dangerous for anyone to have and it's a destructive power.
1) By Ganondorf's magic.
2) The same thing that tranformed him in ALttP.
In LTTP it was the Triforce's magic.
...I think you can make a logical guess as to what I have to say about the "sky Scene." and Can't it just be the Sacred Realm? isn't that just simpler?
No, because why can Zelda enter it at the drop of a hat when it's supposed to be a sacred place with umpteen locks and seals?
nevertheless, it is A golden land, so why not THE Golden Land?
Because from what we've seen of the Golden Land, it doesn't have a golden GROUND.
That's why the sky's black.
If that was the Sacred Realm, and the Triforce was absent, the sky would be blue.
In one timeline.
Even though evidence heavily leans in the direction of TP leading right into LTTP?
2) In ALttP, the Dark World was the product of Ganon's evil heart. The way it works, transforming people into monsters, is a product of Ganon's heart as well, I'd presume, since this feature is only included in that game.
Yes, but it was the TRIFORCE'S magic. Just like Vaati's powers in TMC are the Minish Cap's Magic, and his ascension is the Light Force's magic, and so on. Not his/their own.
BTW, it may not even be necessary for the two Mirrors to be the same one. If TP and ALttP are in the same timeline, the Magic Mirror could still easily be a new Mirror that was created to link the Realms. If they're in separate timelines, then the Twilight Mirror was never destroyed.
Or more simply, why can't they just be two unrelated mirrors that are both magical? We have unrelated magic swords, unrelated magic canes, unrelated magic medallions, and on and on. Why does every Mirro have to be the same one and/or connected directly?
1- ALttP mentions that after the Sacred Realm had been rediscovered, evil began to issue from it. Was the Twilight attempting to engulf Hyrule?
Or more simply, A) A metaphor for Ganon's monsters, or B) an allusion to that "vile wind" that was causing plagues and making people sick. Why does everything have to fucking retroactively connect?
2- The Sages managed to seal the dimensional portals from which this evil was flowing. The portals may appear to work differently in the old SNES game, but might these have been similar to the portals in the sky in TP?
Hell no. The TP Portals were a network of wormholes that connected several locations of HYRULE, and only HYRULE. The portals of LTTP were one way gates to the Dark World. Furthermore, only Twilight creatures could take the TP portals.
I mean, hell, if you're gonna use that logic, then why aren't the LTTP portals and the portal that led to Termina the same? Face it, Zelda has a lot of reoccuring themes that don't have any deeper meaning. Live with it.
3- After Agahnim took over, I distinctly remember the ALttP manual mentioning a climate of fear in some way. Had the Twilight engulfed Hyrule and people had become spirits? TP explained that people who lived in sections of Hyrule covered in Twilight would have no indication of it except for the inexplicable fear.
The LTTP manual describes natural disasters. I think that was what they were afraid of. If the Dark World had ever even partially merged with Hyrule in a TP fashion, I think an in-the-know character like one of the Maidens would've brought it up.
4- When Link entered the Dark World, was he merely 'pulling back the curtain' to see what Hyrule already was? This would explain the ability for the two worlds to interact in limited ways.
GOD DAMMIT, NO! How hard is it to accept that the Dark World is the fucking Sacred Realm warped to Ganon's desires? The two realms effected each other because the Dark World is a mirror of Hyrule.
5- Once his Twilight had engulfed Hyrule, the Triforce would technically have granted Ganon's wish to conquer it, even though he was unable to set foot on the light side and truly interact with his new 'subjects'. Nevertheless, Ganon appeared to be beginning to poke a hole large enough for him to fit through - at Hyrule Castle. This recalls his similar breakthrough at the castle in TP.
Or, he was simply opening a portal so he could escape and take over Hyrule. I think the dominant theory, from what I've seen, is that the Triforce gives you the MEANS to grant your wish, and then lets you accomplish it yourself. It gave him the Dark World, minions, Agahnim (presumably?), and thus gave him the tools to do everything himself.
Going back to Agahnim, I'd be open to the idea that he was Twili. After all, his skin was blue, and he certainly had a way with turning into shadows during his battles with Link. Hard to say, though.
The Twili also can't live in Hyrule without degenerating and becoming deathly ill, the only exception being when Zelda pretty much merged with Zelda.
Again, these are just impressions I get and I merely think it would be an interesting direction in which to take the 'how does ALttP relate to earlier (timeline-wise) games' dilemma. Perhaps the portal on Death Mountain was the point at which Agahnim got OUT of the Dark World, not IN. I imagine it would be easy for him if he were a usurper of the Twili throne, like Zant. That allows a person to manipulate the Twilight in some way, right? Otherwise I don't see how Zant got out of the Twilight Realm either.
I think the obvious implication was that Ganon's magic allowed Zant to do it, not nessessarily ursurping the throne. Though it's my belief that Ganon created Agahnim entirely. After all, Zant was never referred to as an "Alter ego."