While so far we have not seem anything really impressing from her, I still think Big Mon (individually) has the potential to match Kaidou.
That is assuming, as is especulated, that her DF year taking ability has certain triggers, because if she could just use it on anyone she would probally rule the world. Heck, if as seen fear is the trigger, her and perona working together would be invincible.
Not gonna lie, I know he has the match-up, but Brook so far looking stronger than Sanji.
I also think that by now Blackbeard is the strongest character in the series in raw power.
Sure his determination is weak and he is cowardly, meaning he could probally be defeated by any weaker (but close leveled) oponnet who had more tenacity than him, but having Whitebeard´s power (who with this power alone was equal to Roger and "The Strongest man in the world")+ Yami´s power + A resistant body (this guy took WB bisento and not only survived, but was ready to take on Shanks right after) + having the ability to scar Shanks (even if on their younger years), I can´t see anyone, even final luffy, comming close to his raw power (remember, shitty determination).
He is also an expert at lying low and building his forces, so that would be why he hasn´t made any significant moves by now.
You are making very heavy points regarding these changes of scales thanks to involve Yonko on the matter, finally.
I think Lin Lin is the weakest Yonko, and a counter-apart of Hancock. Their abilty works in the same terms, but with fear and worship as differences. So, for Kaidou or Shanks, such things as feelings in a battle will not appear as obstacles to perform their best.
The case of Sanji is special, specially because of Jinbe. To me, in the very moment of him joining the crew, the Monster Trio acknowledgement will disappear. Sanji is obviously weaker than Jinbe and by now, Zoro points to be the best of the world. Things will go smoothly on pairs... anyways, he's got Haki and for that, still is stronger than Brook, but yeah, Brook is a mini-Aokiji to my standarts and deserves a higher bounty.
I agreed with Teach as the strongest.
The main problem of Teach may arise on his childhood issues, when such things as a weak determination would probably come to storm his present, it's just a matter of fact that he had a troubled growth by his photo given in a SBS by Oda. Compared with Luffy, when those things lack in his memories thanks to Ace, Sabo and Dadan.
Anyways, i agreed mostly because of his unique skill to steal Devil Fruits. That trait is what it would make him the antagonist of One Piece. He only has to fight strong opponents and outnumber him in order to kill it. Candidates for that are Dragon, Marco, Jozu, Enel, Kaidou & crew, and even Admirals... only Oda can increase the hype, but the foreshadowing present by now, helps a lot!!