I don't want to check any luggage. I will probably fly with Lufthansa and their carry on baggage restriction are 55 x 40 x 23 cm and 8kg. I hope it will be enough. At least, I don't have a tent/chair with me.
I should be good with a sleeping bag, underwear and a box of baby wipes, right ??
Don't know. Depends on what you want to do before /after the festival. I reckon you need spare clothes as well. And a place to wash your clothes.