Hmm. My best Zeni farm has been dragon ball farming on parallel quest #2. Very easy way to get sellable coins when you beat the random spawning contender after you defeat Yamcha, krillin, and tien. If one does not spawn just retry the level until one does. When you beat them you either get one material item and one key item or two material items. The material item is the sellable coin and the key item is a dragon ball. The sellable coin ranges from common to legendary (as I have seen) and sell for a lot and are very easy to get. As to the second question: I know I have the quest but I'm pretty sure it's one that you can't get unless you talk to a character in toki toki. I won't log on for a while so hopefully someone else answers that one man. Good luck and just look out for all the characters with blue (?) above their heads.