So... what was the pont of... (spoiler)
The harp which can tell when it's owner is lying, the sentient ball of light or for that matter the pig, the princess and the bard?
The harp is an amusing addition but it does NOTHING! The ball of light (possibly the most interesting character in the movie:) JUST DISAPPEARS for the majority of the movie! Once the kid refuses the sword as his reward for the cauldron I thought that now princess will refuse her ball and the bard will refuse his harp. They've all learned (like the kid) that those are just things and they don't make a person. Something like that. But no. These two objects have no purpose whatsoever.
The pig doesn't lead anyone to the cauldron. The fairyfolk do. So, why even have the pig as a plot point? It tells them that The Horned King is after them? Since they are all caught TWICE anyway what does it matter if they know that his army is after them?
The princess' only key plot moment is her deusexmachinal rescue of the boy. Having her show up out of nowhere feels really forced and convenient. There were countless ways to write a better/more natural/logical solution to his plight there.
The bard is 100% useless and does nothing the whole time. His only bug moment is when he asks witches for something in return for the cauldron, something the kid himself should've done (and the kid is in fact the one who asks for the shaggy creature as payment).