its not really just even Luffy who might mess it upThe plan is solid and it probably would work if Luffy wasn't involved. You know he is going to doing something hilariously bad to mess up the whole plan.
I think they will get thier opening when Big Mom opens the chest from Fish Man island.
Pudding seems to have alterior motives, plus theres the fact that Capone seems to not be a character to rely 100% on his word and the whole plan might not work because of Beges misinterpretation.
But yeah the Tametakbo box will play a role