I rewatched those scenes at 0.25 speed to catch all the little details. I won't repost the screenshot with 7th Heaven since it's just up there and I agree it has to be because of the flower, but:
As you can see, the Nibelheim entrace is right there in the Gongaga scene (the first pic). In the last pic, which is from chapter 14, it's way more difficult to tell what the hell is going on: there is a place in the middle, but it doesn't look lik it's the Nibelheim entrance. It's also connected to the bridhe for some reason.
And the second pic in the middle, you can see Stargazer Heights in chapter 9, between the water tower and the bridge: to me it shows the connection of the scene of Cloud remembering the promise between the place he made it and the place he actually already did it. So I feel pretty sure that the scene it represents is the one at the end of chapter 4 of REMAKE when they have that little convo about the promise.
As for the chapter 14 picture... someone said on Twitter that the Black Whispers were corrupting Nibelheim, which may be true (they made it even more obvious than the Midgar changes in REMAKE). I posted their threads here I think? I can reshare if needed, it was interesting. What's interesting to me is that the shape of those two Lifestreams scenes
are different and the second one looks maybe more like Cloud's memories. On the far left we can
guess that maybe there is a building there and I wonder if it's 7th Heaven, as it was in Tifa's memories. I say that because of the very straight lines under the rocks, that don't look much well... rocky so to me there is a structure there that is hidden.
Then you get Tifa's house, followed on the right by an empty area: is it the town entrance or the water promise? It doesn't look so, it looks empty to me, just like in the OG there was an empty space. Then, the bridge. And I do wonder if the entrance of Nibelheim, which in Tifa's case would represent her hopes of reuniting with Cloud again, is supposed to be the beginning of the Nibelheim incident for Cloud... which would be scary if it was missing? We are not seeing the whole scene, that much is certain, but it does feel ominous and wrong.
So to me, maybe the Black Whispers are corrupting the Lifestream... but it also does look like they are trying to destroy Cloud's memories, to prevent him from ever coming back from his mako poisoned self. Now what if Tifa has to spell out memories to help him
rebuild his own memories? Like she tells
her version and he tells
his version; a bit like what they did in Nibelheim in REBIRTH.
