Whole Cake Island really is something else. It just clicks, especially in the manga, and it's by far one of the better anime post-time-skip arcs as well.
Instead of Sanji getting the nepotism we typically see in series, his life is the exact opposite: everything was on hard mode from day one. Then, we got Big Mom's flashback/the Tea Party, some of the legit craziest shit that's ever happened in the series. I think the rest of the arc DID have a bit of a problem living up to the Tea Party's hype, but, overall, what an arc.
I'm still hoping Linlin comes to Elbaph, now. I've spent a lot of time saying how I believe Charlotte Linlin will become an ally, through her gaining her full memories, and realizing that Mother Carmel is evil, as well as most likely having Mother Carmel's lingering Soul/Spirit exorcised from her (by Brook and Sanji, with Pudding helping out with the memories).
I believe that after Linlin's rampage in Elbaph, Mother Carmel pushed her luck to far. We see this here:
Mother Carmel knew A LOT of damaging information, and had already lost her connection to Elbaph. I think the decision came to the Gorosei, and they rejected Linlin, thinking she was just a crazy child they couldn't control. If she had randomly attacked a Giant elder, and killed him that easily, would she be more of a threat than ally?
IMO, the Gorosei (who we know work with CP0 Agents directly, and we know this was a CP0 agent because of his mask), are the ones who declined to take on Linlin.
So, Mother Carmel was left with a crazy child. Then... she decided to use the darkest form of her power, it's Awakening: Soul Transfer.
I don't think Linlin ate her friends. I think Mother Carmel used her knowledge of Linlin's mental illness, to feed her enough of her favorite food so that Linlin would be unfocused, and Carmel could easily take her body over, and force her Soul into Linlin's, with this process putting Linlin into Carmel. However, Carmel misunderstood Haki, and, due to Linlin's natural CoC, she resisted/rejected the power.
Carmel took over PART of Linlin's Soul, and, when Big Mom is fed/satisfied, Carmel maintains control. BUT, when Linlin sees something that triggers her original Soul, or she gets hungry, her original self starts to take over.
O-Lin was the ultimate form of this: O-Lin proves that the original Linlin is still inside Big Mom. It wasn't Charlotte Linlin having Amnesia. IT WAS MOTHER CARMEL FALLING UNCONSCIOUS from being in sea water for so long, and it took LINLIN falling unconscious from Queen's attack, for Carmel's personality to be able to take control again.
O-Lin wasn't a case of Amnesia, it was proof that the original Charlotte Linlin is trapped inside off a chimera Soul creation, like Full Metal Alchemist shit. SHE'S STILL IN THERE, and Brook and Sanji need to rescue her. I think this will be a combination of Brook's Awakening and Sanji's cooking since Big Mom is Music and Food themed. Also possible Sanji infuses CoC into his Cooking. CoCking Haki.
Once Carmel failed to take over Linlin's Soul years ago, THAT'S when Mother Carmel/Big Mom, the monster formed from Carmel's evil failure, ate the other Sheephouse Kids. I also think their Souls are still in there, and that they'll become Homies after Mother Carmel is exorcised from Linlin's Soul.
After this, Big Mom will finally become a full ally.
BUT, I do hope she shows up here, in Elbaph, first, and fights Imu to become a hero of Elbaph. The parallels between Loki and Linlin as being victims of the WG blamed for things they aren't at fault for, and their clear love for Elbaph/it's people, make me believe Big Mom is showing up here.
I need to see Loki and Linlin hit the Hakai together.