Saitama is known to kill people with one punch (Hence the name, and title.) If Martian Manhunter used telepathy on Saitama, and forced him to punch himself in the face as hard as he can..could Saitama survive his own punch?
Yes, best to disregard SOS Superman, and Superman Prime One Million due to lack of feats.
Prime Trapper is a tough one here. Reason? Time Trapper has been many different people through out comic history. Once he was Vandal Savage, and many others. The real Time Trapper, not the one's we see fighting the Legion is actually Entropy it's self.
Yes, you're correct with the feat statement. We don't really have enough feats from Fujitora yet -- besides the meteor, and gravity increase powers he has shown.
Akainu has already defeated Akoji after a ten day straight fight. So Akainu wins. Current versions Akainu wins even more so.
Kizaru vs Fujitora is the more interesting fight. Kizaru has both a range and speed advantage over the blind admiral. However, there are few factors that might play out in Fujitora's favor.
Factors to consider:
1.) Devil fruit powers: Fujitora's gravity powers are a good counter against Kizaru's light based powers; since gravity can effect light. We saw the the gravity field Fujitora put around himself to repel the meteor he summoned; the gravity field should work against light base attacks.
2.) Personality: Kizaru is best described as a "troll"; like Aokiji he seems to be lazy, and nonchalant. He likes to play around to much. He is fighting a blind man, and knows he can move super fast. So, he would probably go in close counter combat with Fujitora thinking he can attack, and retreat if necessary. If he gets to close he might get caught in Fujitora's gravity field.
Crossbones, or Cain. Although, as mentioned before..a female Juggernaut would be interesting to see. However, from what I have learned about Cyttorak there are is one thing that you have to consider; will said avatars powers mesh well? Do they draw powers from another source that is compatible? We see that Cyttorak doesn't like to share his avatar with others if their goals aren't the same -- like when he took away his powers from Cain when he got power ups from the Uni-Power, and the Serpent. He allowed Colossus to have both his, and the Phoenix Force because they both are tied in with the aspect of destruction.
As for other candaities not mentioned I would like to see are:
Jaime Mardox, Boom Boom, Deadpool (Not really, but would be a funny one off before handing the power over to Cain.)
I like the others that have posted before me really wish Cain to return being the Juggernaut. Cain will most likely return to being the Juggernaut later on, hopefully not depowered this time around. In the mean time if they're going to have a new avatar for Cyttorak then I hope it's someone that can add more interesting aspects. Don't get me wrong the original Juggernaut was fine the way he is, but Colossus didn't really add anything except for metal skin (cosmetic change). I want the new avatar to have additional powers that will mesh with their new found super strength, and invulnerability.
Another thing I want to see is more Cyttorak. Outside of the old comics where he kidnapped Galactus, and his heralds along with Classic Doctor Strange, and banishing Colossus with a portion of the Phoenix Force he really doesn't have a lot of feats going for him. Would love to see more of what he can do, and where exactly he measures in the whole cosmic hierarchy.