Big Mom is pretty open about her villainy, cares very little about actual money(didn't care when she learned she was losing a lot or when Luffy offered her some), and is really into family and amassing power. Carmel was crafty, selfish and was shipping out power for wealth. If she is in there she doesn't do much aside from pushing Big Mom own flaws.
I don't think it's impossible but I'm unsure why Carmel would do it with so little of her left(just to f**k with Linlin or it failed?) or why Oda would do it(he never cared about making the bad guy suddenly be good before).
I imagine we could have some of the kids still alive shipped by cp0 that would have killed Carmel in front of a delighted Big Mom but I don't see Oda using Carmel as a explanation but rather as a lesson.
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I wonder what's up with Napoleon and Zeus. Are both amnesiac or just Napoleon? Or do they their memory but were reverted to 5 years personality making them(Napoleon) play along?
I doubt that, Napoleon wasnt around as LinLin was a child. So he basically couldnt have the memories of back then. He was the last homie to be created and it just was made as Big-Mom was well in her 40s already. The whole homie thing is confusing though i will give you that. We just can wait what Oda comes up with lol. Also i hope in next chapter we see at least a little bit of action with LinLin and the others xD