Who are these guys seen in chapter 691? SPOILER ALERT

Who are these guys? What are their names and their positions?
These are the Gokage (lit. Five Shadow), the first Kages from each country. Their names haven't been told yet, but by their appearance we can deduct which Kage ruled which village.

First panel: The first Kazekage. I'm doubting between the third and first panel on who the first Kazekage might be. But given that the third panel resembles a Tsuchikage more, I deduct that this is the first Kazekage.

Second panel: First Mizukage. The razor teeth follow the trend of the shinobi swordsman who originated from the village of the hidden Mist.

Third panel: I'm guessing that this is the first Tsuchikage. I'm not sure because I can't base this answer on the fact that he's aged. The facial hair however does hint at a resemblance between Oonoki and other Tsuchikage's.

Fourth panel: First Raikage due to hair. We can assume that he's coloured. This follows the trend that most villagers from the Hidden Cloud are in fact black.

In manga chapter 648, pages 10 - 11 and 12. We see Hashirama meeting with the first Kages. These are the same Kages as shown in the panels