Wrong. Wapol does not meet any of the criteria I listed that Caribou meets which will cause him to be a crewmember. All Wapol does is change from evil to not evil, he does not do any of the things that Caribou has done which implies Caribou will be the next nakama. You have completely misread my argument.
1. Caribou tries to join strawhat crew, but it is fake.
2. Caribou has some kind of back story with the Marines, who he apparently has a high bounty for killing a great amount of. We don't know why, but he states that the Marines are "hypocrites" and gives an explanation of why they are in the first chapters he is introduced.
3. Caribou is doing something that no one ever except for a strawhat crew has ever done with the straw hats, travelling with them from one Mega Arc to the next Mega Arc. He is a part of the transition from Mega Arc Shabondy/Grand Line to Mega Arc Fishman Island/New World. This is extremely significant in literary thoery, which Oda, over the years, has demonstrated he uses constantly (he is a good author).
4. Caribou describes himself when he describes the Kraken, while on Luffy's ship, and then Luffy states he's going to tame the Krakken. This is called a parallel and it is being used to foreshadow the next crewmember, Caribou, who is incredibly ugly and mean and a theat to sailors (he is currently trying to destroy the straw hats and steal their ship, the krakken is going to try and destroy the straw hats and crush their ship). Luffy is going to tame the best.
5. We have had several themes with new nakama, one theme we have not had is redemption or salvation. Caribou is perfect for this.
Then there is Moo Moo, who is a recurring character from Arlong Park, who in this specific instance delivering Caribou, by himself, to the Strawhats, is a demonstration of Deus Ex Machina (eg, Caribou is only stuck with the strawhats specifically because he used Moo Moo to get to them, if he had used any other sea monster it wouldn't have worked, if he didn't use a sea monster at all, it wouldn't have worked, instead he chose to use a sea monster that specifically runs away from the strawhats at the sight of them, causing Caribou to be alone with the strawhats, deus ex machina).
(sorry for all the bolding I just realized I was doing that, my bad habit)
Oda did not need to use Moo Moo, instead he specifically chose to use Moo Moo for the specific reason of causing Caribou to be alone with the straw hat crew. Then they encounter the Krakken, which is a parallel to Caribou, and Luffy says he is going to "tame" the beast, a foreshadowing of changing Caribou from "bad" to "good."
Luffy has stated (canon) in the Arlong Park arc, outright, that he does not care about the past of his Nakama, so Caribou's evil past does not disqualify him from the Straw Hats. Neither does his ugly appearance, and that is what's going to be shown through this arc.
They are going into the New World and Caribou is going to become a New Man and join the Strawhats, adding a logia power to their arsenal.
At any earlier point in the story, no logia could join the Mugiwara, because it would tip the balance of power (they were too weak to have one without being overpowerful for their environment). There's no point in having the Strawhats defeat Logia Caribou so that we can see they can beat Logias, we've seen this in Sky Island already, now they are 100x stronger than they were and at least Luffy can use Haki, which we know can combat logia, obviously he would beat the shit out of Caribou. On top of this, we've seen the demonstration that they are now way stronger when they one shotted the Pacifistas that previously could singlehandedly challenge the entire straw hat crew combined. It would be redundant for Caribou to just be a "proof of strength" character.
Since the straw hats are way stronger now, a logia doesn't overpower them anymore, and in fact they need a damn logia on their crew (paramecia and zoan are already there with robin and chopper (captain doesn't count)).
Also, we don't know what his logia is yet but I predict it will be nowhere near as good of a logia as Fire, Poison, Lightning, Magma, Ice. It will be less obviously powerful than these for whatever reason, specifically because Oda wouldn't put the most powerful class of logias on the strawhat crew (he will have to use his intelligence to improve his power, and will have room to grow).
The "Krakken" is a parallel to Caribou, they are one in the same. Outwardly ugly, powerful and mean and seemingly hyper violent. The Krakken is mythically an enemy of sailors and destroys ships, Caribou is currently trying to steal a ship and kill a bunch of sailors (pirates).
Wapol meets none of these requirements.
Wow.