I can't seem to find any guides about how these quests work. It's telling me to visit Maleria, and I have, but no sign of the item there. Do you have to complete a quest for the NPC she sends you to in order to get the quest item (I hope not, because silly me already did all the quests I have access to already)?

You have to complete a quest. Once you completed the quest, you will receive a piece of the bracelet as part of your reward. You take the piece to Shinwa, she will accept it and tell you which quest giver to go to next (sometimes it is the same one). There are the 5 pieces of bracelet so you will repeat this process 5 times.

Most people do Shinwa's Quests first, if they do her quests at all.

You can buy her bracelet pieces in user shops and turn them in, but the reward isn't worth the expense.

Mmkay, note to self, do Shinwa first from now on. Thanks!