The 1st doesn't really need an explanation imo, but he can heal himself without forming seals so the 3rd couldn't kill him. (Also I am assuming the 3rd does has the weak point that naruto exploited). With the Bringer of Darkness genjutsu, it would be a lot easier. Maybe using wood style to grab his arm and make him stab his own weak point. That is assuming he can figure out that he needs to do that, but I believe he is intelligent enough.
The 2nd was highly skill in s/t ninjutsu, could use Bringer of Darkness, and (although it wasn't perfected) could use Impure World Reincarnation. Therefore, he could render the Raikage's eyes useless, have backup with Impure World, and be able to use s/t to his advantage. It might take him a while to figure out what he needs to do, but once he does Bringer of Darkness used in combination with his s/t jutsu, it would be simple enough (he could make a noise so the Raikage would attack not directly towards, but in the general direction of the weak point, use s/t, and use the momentum from the Raikage's attack along with his own strength to push the Raikage's arm into the weak point.)
The 3rd was said to be the most powerful hokage when he was in his prime. He would have Enma to help him out. And since no sealing jutsu are allowed he can't use Reaper Death Seal. His only chance would be to trick the Raikage into hitting himself. Though he is smart, he doesn't have the advantage of using Bringer of Darkness, so it is possible the 3rd could finish him before he figured it out. So in his prime: undecided on who would win. In his old age: 3rd Raikage wins.
The 4th has FTG and rasengan, that's all he really needs. He is fast enough to dodge Raikage's attacks, and would just need to figure out the weak point thing. If he figures it out, which I believe he would, he could just do what naruto did.
The 5th gets smashed.
If we count Danzo as the 6th, he may have a shot if he uses those eyes on his arm for Izanagi, finds the weak point, and is able to trick him into hitting it. Undecided on this one though.