1. There are 2 elves in my tavern. A dwarf enters and starts fighting with one of my elves. The dwarf wins. Normally my other elf would leave the pub, because there was a fight, but my dwarf wants to fight this elf. Does my elf leave or will there be a fight first?
Fights are always done first. When all fights are over, your elves will leave.

2. It doesn't happen very often, but what do I do when a customer has had his maximum number of drinks? For instance, i'd like to keep my elves at that point, because they aren't drunk and will bring a lot of points.
When a customer reaches his maximum number of drinks, he doesn't want an extra drink anymore. Even if the dice says so. Your customer will not get annoyed anymore.

3. In the bidding phase, in case of a draw, a human will go to the tavern with 'customer with highest value' What does it mean?
The human will go to the tavern where the customer is which has the highest value of points at that moment.