do you have food and drinks before the performance

I usually go to a bar/restaurant to get good food and a decent cocktail. There is plenty of unhealthy food options at the festival...I mean TONS of options. Wine and beer can be found at all stages but the quality is not the same everywhere. You can always leave the secured area to find some good grub - the bracelet allows in and out entrance.

There's a bar in the entrance area and a cafe. You can bring f&b into the concert hall.

Yes, there are lobby bars that serve wine, beer and snacks. There is also a restaurant named "B-Side" at the ground level, but may require reservations.