This is interesting. Ninjutsu and taijutsu doesnt really work on the 3rd raikage therefore genjutsu would most liekly work and the 2nd mizukage is a genjtsu specialist. Saying the the 2nd mizukage would still need to use ninjutsu on the 3rd raikage and i dont see him acquring any jutsu that could harm the 3rd.
Plus the 3rd raikage stamina is out of this world, he is the only person who actually fought a bijuu and came out with a draw. Minato couldnt face the 9 tailed head on and draw, instead he sealed it with cost him his life.
3rd raikage wins this due to his defence, stamina and speed