This is how in my opinion he will connect it and how its not a mistake. We all saw Obito looking at the 4th hokage head and assumed this is an error. Hold on because kishi wouldnt make a mistake that huge.

In this page we see the 4th Hokage telling the Raikage next time we put the title of kage on the line

http://www.narutobase.net/manga/Naruto/542/17

This to me is the same time as the war,, the exact time while kakashi and obito trying to save rin. the 4th hokage was at the other place defeating all the shinobi by himself and then regrouping and running into A and B. How do i know he ran into A and B at the war well because it was the great war ofcourse and heres another proof point.

http://www.narutobase.net/manga/Naruto/543/12

He is now clearly Raikage , so it was certain he would become a kage when he ran into yondaime. This tells me that kishi can connect it all by these chapters alone.. The 4th hokage was already decided... the 3rd hokage was old and had done his job for many years probably more then 40 years of work. So the 4th hokage was basically he met all the measurements required to fill the roll just that the war needed to be over and he needed to come back and do his ceremony and wat not.. plus its not a good idea to elect a new hokage in time of war when the 3rd has the most experience..

So there you have it. 4th hokage was already decided and so was the Raikge... thats why he said wat he said to A back then..

P.s thats why i believe he will clear up the whole Obito thing the clues are all in the manga , kishi aint a joke ,,, i still dont feel he is the real obito but this aint the thread to discuss it but who knows lets see