Seriously what would be the point of Pudding telling Luffy, Nami, and Reiju that all the Vinsmokes + Sanji is going to die at the wedding? If it's supposed to be "secret" she shouldn't be telling them that in the first place. If Big Mom plans this, this is already disobeying Big Mom's plan at hand. Something is definitely fishy here.I was about to call bullshit on this theory of yours but I honestly can't consider myself an accurate barometer for OP after this week. It could happen. Literally anything could happen.
This doesn't mean Pudding is entirely innocent mind you, but rather she's trying to use Big Mom's system against her to cause chaos at the wedding.
Chaos at the wedding means the Strawhats and Pudding can both escape the island unscathed.
Pudding is also a habitual liar as well, which we've already known for weeks now from the context clues Oda has given us.