Master X:
New Locations:
2. Not so sure about that, for one thing it's probably where most of the Ultimate Weapon control facility is underground. The only reason we'll be there is if we were allowed to explore what remains of the facility but that'll mostly take place underground (maybe in the forest there's another secret entrance but that's all they'd use the forest for).
3. Top right I can maybe see getting too if they reveal a passage to it from Frost Cavern, but the bottom right area? The only way I can see to it is either by flying or letting us surf through the various rivers.
4. Well considering that's where we found Zygarde and he just gotten a batch of new Formes...
And let's not forget they can create new places within old locations, like remember in BW2 them adding the Castelia Sewers?
Moondial: The moondial thing is just someone saying they exist, they're not saying there's a moondial equivalent to Anistar's Sundial.
Idol: The idol looks like a Hawaiian tiki to me. I think it was decided there's really nothing else to talk about with the Strange Souvenir, we know nothing about it or what's it representing so really nothing to talk about. I suggest waiting until XY2/Z is released before we decide it needs any more speculation. If it does anything it'll be in XY2/Z; it's not a Key Item so its transferable via a Pokemon holding it.