The biggest change so far as the book goes from West End to Broadway is the switch of order at the start of act two.
At RSC/WE, it went from Telly to Entr'acte, which flowed into When I Grow Up and the Lavender speech, followed by library.
Broadway seems to have Telly, short Entr'acte to clear stuff, Lavender, When I Grow Up and finally followed by library.
I'm too used to the former at the moment, but I'm curious why they are trying to flip the sequence. Part of the reason, for me, why When I Grow Up works so well is as it's a massive "we are back" song, that effect is diluted slightly with a plot speech before hand.
We'll see how it evolves in the coming weeks