A quick translation and other bits I've read:
Avatar creation is for the online elements
The guide doesn't say who Ishmael is. Konami and Kojima Production asked to not reveal it. It will be revealed in an optional mission after the main story has ended
50 main missions
157 optional missions
Quiet will leave you after mission 43 and to finish her story you will have to find her after the main one is over STORY SPOILERS HERE
The last mission is against the Metal Gear controlled by "the floating kid"
Yong was right. There is some kind of infection. Skull Face has it. Code Talker has the cure. It was in the bio of Skull face, I stopped reading because it would be too spoilery
Quiet goes to the hospital to kill Big Boss and speaks
BIG SPOILER The guide refers to the protagonist as Ahab and a DNA test says he and Eli are NOT related
The fire guy is Volgin. You have to get his body in chapter 2
Direct translation HUGE SPOILER "When Ahab meets the ghost of Paz the first time at Mother Base, there are clearly TWO versions of Big Boss on the chopper"
The medic and Ishmael are the same person. Probably the real Big Boss, but I don't want to read more
Pictures of the last 2 missions: http://imgur.com/a/zb0Wk
Pictures of the Boss pages and bonus costume: http://imgur.com/a/x2mYI
The bosses are Skulls (Fog version mission 1 and 6, Armored version mission 16, 29 and extreme 37, 42), Camo version mission 28, 46), Quiet (mission 11 and 40 extreme), Man on fire (prologue and mission 20), Eli (mission 23 and optional 113), Sahelanthropous (mission 12, 31, 50 extreme)