Brain tree:Personally, i've never finished a brain tree quest, because i only had part of the answer. i really have no idea how to get the information he wants, but if you do an esophagor quest, he might give u part of the answer.
The Esophagor:I really hate this guy. i spent like 40,000 np altogether and he gave me a stinkin bag of nuts. i advise you, don't do any of his quests if they items cost more than 5000np. also, if you've failed a brain tree quest, the esophagor might give u info that was the answer to the failed brain tree quest.
Edna: bad. i hate her. i spent 4000np (not a lot, but....)and she give me a roast tentacle.i also heard that she can turn your pet into something else.
Taelia:The good thing is, you get an avatar when you do a quest for her. Do not do the quest if the items cost more than 6000 np. I'm not saying should can't, but you shouldn't. She usually gives you 1000-2000 np, and item, and a magical snowball if you spend under 6000np.
Kitchen Quests: Don't spend too much. he usually give you an item worth like 300 to 2000 np. a baddie.
yup. that's it.