So the Harry/Hermione dancing scene is not during the Wedding.. see, told you that Kloves will mess up! I will tell you how Ron will be portrayed.. as if he is this twin brother of Voldemort who hates to see anyone happy! when clearly Ron is the only character who is all heart.. don't be surprised if the film has:

1) Harry and Hermione dance out of sheer happiness after Ron has left them during the Horcrux hunt *rolls eyes till they ache*
2) Voldemort and Ron plot together to bring Harry's downfall, since, you know, Ron is more or less a villain according to Steve Kloves
3) Harry and Hermione marry in the epilogue and have a cute family *not even bothering to roll eyes*

Steve Kloves must have had a field day, butchering Ron and making him look like he is the worst character in HP and make Harry look like he is a saint!
I know my rant is totally irrelevant to the 'sneak peak' context, but I think it is high time we stop making excuses for the supremely 'un'-talented Steve Kloves and actually have some canon moments in films!

P.S: one more doubt.. since they stupidly burned down Burrow in the 6th film, where exactly is the Bill-Fleur wedding taking place? They rented Malfoy Manor for the evening I suppose