In short:
All Big Mom does is trying to relive her 6th birthday. Totto Land is the orphanage, the family are the orphans, every party/wedding is used in order to recreate Big Mom’s 6th birthday.
Mother Caramel is replaced by a photo and Big Mom herself replaced the actions in order to keep the (fake) dream of Mother Caramel alive.
Chapter 900:
Shonen Jump revealed that this was the last chapter of Whole Cake Island arc. So how can this open ending be an end of an arc? Well if we connect the dots it could be obvious.
History repeats itself:
It was Big Moms goal all along to repeat history. But nothing was enough to come close to her experience back when she was 6 years old. But now the cake did just that. The cake brought her back to the state of mind ,back when she was 6. Everything in Whole Cake Island is fake but the cake is real.
Because the cake is real the chainreaction will also be real. Big Mom ate her family when she was six years old. Right now Big Mom is eating her children.
Perospero:
He makes us believe that there are only 3 options after Big Mom eats the cake:
1. Mama dies to the poison, thus the end of the Big Mom Pirates
2. The poison doesn’t work but the cake doesn’t taste good
3. The poison doesn’t work and the cake is delicious
This is important because the whole Arc is about misleading the reader, misleading characters, all the lies and secrets.. We as the reader are presented with 3 options and we know the outcome because yeah obviously it was option 3 (and there wasn’t even poison!)
But this makes it way too easy and incorrect. The 4th option wasn’t mentioned because no one ever seen Big Mom in this state, well only Streussen and without a doubt he will be terrified to the max. The absolutely amazing cake brought Big Mom into a overhappy canibal-like state.
The last time this happened she had been eating her family.
Possible outcomes:
Big Mom is eating her family, the Big Mom Pirates will have to fight her, to protect themselves and to protect the people living there. But yeah, try to stop Big Mom now.
It is dark, but inside Big Mom there is a “pet cemetery”, and you just love your pet. Inside her is a graveyard of people she loves: The orphans, Mother Caramel and now her own childern will join that cemetery party.
Because if the cake did indeed trigger Big Mom the same way as the semla did… Why would the outcome be different now?
No one would want to live in Whole Cake Island anymore, Maybe all, maybe just some of Big Mom’s childern will be eaten by her. And now a Yonko is defeated “thanks to the Strawhats”.
The blame? Pudding will get the blame because she made the cake.
Katakuri is well “friends” with Luffy, they have huge amounts of respect for each other and
he is still safe in the mirror world. Katakuri lost all the respect of his own family. Katakuri and Pudding both have no reason to stay there and probably will have their own journey.
Maybe they will look for Lola, wanting to join her, maybe all surviving Big Mom pirates will join Lola with their new goal: to find their own happiness and love.
Problem:
If Big Mom got her Devil Fruit power by eating Mother Caramel, then eating another person with a Devil Fruit kill her. So maybe she will eat come citizens and some children without Devil Fruit powers.
But something big and dangerous is going on right now. Big Mom finally got what she wanted: to relive her 6th birthday and it destroyed everything she build up.
*Theory by ChuckTalens
