@Hanz:
1)she's most likely has a high rank in big mom's pirate crew, judging from how she was seated right next to her in their debut back in chapter 651.
2)being such a high ranking member, she must be very trusted. therefore, it's unlikely she would betray big mom.
3)just when she lead the strawhats to the meeting island, pekoms disappeared. why is that? most likely because she's leading them into a dangerous area that only the residents know about.
4) pekom's message?
1-2) she is also one of her daughters,and that was probably the period the marriage was being arranged in the first place,so she doesn't really need to be an high rank officer to be there..also,she seemed displeased by moma's actions..of course we saw everything out of context,but still,is far from a proof.
3)pekoms was alone on the ship on enemy territory,also we don't even know when he has been snatched,for all we know,he might have been captured way before pudding even met luffy
4)pekom's message what? it can mean tons of things and none of them specifically point at pudding.If anything,pekoms didn't know luffy met her,being on the ship
another strange point in this whole plan is that it's luffy who indirectly approached pudding,and not viceversa..it's him who ate her cafè,
–- Update From New Post Merge ---
@Tom:
It also seems odd that Pudding has had the time to meet Sanji. Mom was informed about Sanji's arrival for what I assume to be the first time last chapter. I'm not sure how Pudding could meet Sanji without Mom knowing anything about it.
we have a "couple of days" in between the last moment we saw sanji and the moment we started following luffy's group.During that segment of time is completely "on schedule" for big mom's ship to stop at cacao island, make the two future husband and wife met at least one time before the cerimony,and then continue towards whole cake island that it's just 1 day of navigation from cacao island,just in time for him to be "just arrived" when big mom's ask about him.
so depending on how many " a couple of days" are for oda and how far sanji was from cacao island last time we saw him,the time fits completely.
cacao island being considered an "entryway" to big mom's terriory helps with this hypothesis,since it means she is on the periphery of the archipelago,exactly where sanji was last time we saw him.