There was also Greg's "Planned Vs. Not Planned" topic on the old forums. I failed to find a google cache of the first page, but there's one of the last page, with a few posts of Greg's:
Pretty sure in the firstpost he said that the three = one thing wasn't planned (despite the logo), and there's one line in one of the posts here that seems to confirm that. Unsure though.
Nixie has a map in her hut with one larger planet surrounded by 2 smaller ones.
This is actually evidence against the idea that Spherus Magna was planned originally, for a few reasons:
1) The most important object for Nixie's purposes is the Red Star, so if you were right we should see at least four objects.
2) There's also a small moon orbiting AM, which has been depicted in their skies, but never Bota or Bara Magna. So there should actually be five objects (or four if just one of the others were visible perhaps).
3) The words "Mata Nui" point to a spot on the large central one, showing that it is Aqua Magna, and the map is depicting only things that orbit AM. This would be contradictory if either of those dots referred to Bara Magna, which even at that distance should look so huge she wouldn't make such a major error.
4) One of the orbiters is smaller than the other, so if the central one was supposed to be Bara Magna, that would be wrong because Aqua and Bota Magna are the same size.
5) Greg confirmed that you can't see those from Mata Nui Island due to that side of AM always pointing away (much like our moon's far side). This was almost certainly because they were added later, to explain away why Nixie didn't know of them.
The sundial underneeath Mata Nui points towards 4:00, which looking on a map of the MU, does in fact lead to Karda Nui. (We do find out later this is the sundial's purpose.)
I don't see how you figure. 4:00 on that map is due east, and there's nothing that way but the left side of the giant's head. It would have to point due south to do that. I suppose being underground it could be aligned any which way, so you could be right, but then how would we know? Am I missing something here?
Also, Greg confirmed that he didn't invent the Sundial; fan popularity of this idea made by the MNOG designers was what led him to canonize it and assign it a purpose. It only pointed to Karda Nui after being removed, and possibly realigned. In fact, the actual design of the sundial (well, the number of spots, anyways) wasn't canonized until we did a BSS project for it.
You are correct about the face clues; those were all intentional.