I've been closely following this game's development to the fullest extent allowed by my limited access to information, so I'll clarify some things for you.
The picture in which you see the touch screen controls is what, as was last reported, is known as "Precision Mode" (the 505 Representative working on the game said this name wasn't final, and thus it may be different now). This mode, activated by the button with the target on it on the bottom of the touch screen of the picture with the inventory shown, is tended solely for precise building and breaking of blocks. It is not intended as the main control scheme for general play. As the 3DS lacks a second stick (and the New 3DS's stick is unfit for precision aiming), the main control scheme consists of aiming with the Circle Pad. When the Circle Pad is pressed slightly in a direction but not fully, you will see a targeting reticle indicating where you're aiming, but you will not move. Press it fully or nearly so, and you'll both aim and move in that direction. In addition, the X button behaves as a lock-on feature that can be used to secure your aim to a particular enemy until it dies or until X is pressed again, allowing you to move and aim in different directions.
In short, both 3DS and New 3DS possess this Circle Pad-oriented aiming method, meant as the main control scheme.
As for the inventory when referring to the picture with the inventory on the bottom screen, I believe you can select which item in your hotbar you wish to switch to with your stylus, as well as L and R of course. I don't recall any information discrediting touch screen control of the hotbar, but I may have forgotten something. As for the picture with Precision Mode displayed, the inventory management system is actually really neat. On the left side you'll see the best of every kind of tool you currently possess in your inventory, as well as the weapon you last used when you opened Precision Mode. Tapping this weapon slot while it's already equipped will switch through the different weapons in your inventory. Along the right is a scrollable list of all building materials in your inventory, thus you don't have to leave Precision Mode to change materials.
In addition to the Map, Precision Mode, Inventory, and Stack to Chests buttons you noticed, there's a dim button above the Precision Mode button that is for dropping items, in which you drag an item from your hotbar to it to drop it (this is intentionally deliberate so you don't accidentally throw items out during intense situations), and to the right of that is, of course, the NPC Housing button.
As for the game's version, the last word is that the game will be 1.2 with some features from future versions. The interface is 1.3, as Redigit's request. In addition, you'll notice the use of fishing rods and minecarts in the trailer in the first post.