Wow lots to catch up on now lol...
Maybe I'm just tired, but this seems the most logical explanation:
However, I think that there might be caves/land below the cliff, which could be explained by the full land-covering theory or just rubble getting scattered over Mata Nui in in the crash. A giant robot crashing would stir up that seafloor pretty bad, I think.
Isn't that image saying that Mahri Nui itself was the cliff? But it was clearly stated and shown to have landed on a pre-existing cliff, re: this image for example.
Along these lines of discussion another question comes to mind. How on earth did Voya-Nui float perfectly back to the hole it left in the ceiling of the MU after the chord was broken?
It was clearly stated that the Staff of Artakha directed it there telekinetically as part of the damage-healing process.
My best guess is gravity, and the weight of the whole island keeps it from floating away.
No, the island naturally floated. Gravity alone wouldn't do it.
magnetic force, generated by the Staff of Artahka.
Sort of -- I would say telekinetic. It's mostly rock and there's no evidence it's magnetic rock. (Of course, wayback in my old Wacky Physics topic I pointed out that pinpoint-cloud magnetic fields could be how telekinesis operates.)
Well yes , but the island had floated away from the hole after it surfaced, so how did it get back to the EXACT place and in the EXACT position needed in order to fit? Luck? Magnets? Ocean currents?Wait, also, when Mahri-Nui hit the foor it hit a field of airweed, where did all that come from?
If you're asking why there happened to be airweed growing there, BS01 states that it was native to the Great Sea (Aqua Magna), and Mahri Nui didn't fall until the giant robot had been resting there for 700 years, plenty of time for it to spread to that spot.
The thing is, when was the Staff activated? Exactly when the Toa Mahri destroyed it? And that wouldn't of been possible, as the Staff drained the water out of the Pit(Mahri Nui was around the same area as the Pit), so the Toa would of "drowned on dry land".
It really doesn't matter. If slightly before, it would not have been able to sink -- that was the whole reason they had to blow up the cord. If after, Voya Nui would have floated peacefully until it was activated.
And I don't quite understand what you mean about the draining thing. The quote you posted seems to imply the staff did not drain the water:
The Pit has an entire dome to itself, filled with jail cells housing the universe's most notorious criminals. After the Great Cataclysm, the Pit was a submerged wreckage, containing little more than Rahi and a few Zyglak. After the Staff of Artakha was used, the Pit was restored to its former state, and the water within it was later drained.
Emphasis mine. And Mahri Nui obviously wasn't in the Pit anyways, so water out of it wasn't drained. If you're asking how they were to survive, had the Ignika not intervened, they would have simply lived in water for the rest of their lives -- simple.
But if the Staff did it it would also be fixing the MU ceiling and would end up cutting it off from getting inside....what I mean is that if the staff was the means of pulling the island, I would be active and if active also fixing the rest of the MU, including the hole tgat the island needed to fit through. A fixed hole would bar the island from returning inside?
What fishers said. Plus, it's quite reasonable to assume the hole it created was slightly larger than it and that healing the outer hull (generating new material) takes a lot longer than telekinetically pulling old material back, so in the time between the activation and VN reaching that spot, whatever was healed still left a hole larger than VN. Think of it like this -- what takes longer in real life -- to grow a coral reef or to push a chunk of reef through a hole even as coral grows to fill it in? Pretty obvious, I would think. Besides, why bother returning VN at all if healing missing material was so easy? Just wave the staff and there's new land there. Clearly it wasn't that fast or powerful.
And there's no "if" there -- the staff was what pulled it in.