bard quests i never do, avoid completely as well.
Yeah, I was doing two unrelated quests and found a couple of those instruments in different chests, but this playthrough I knew better than to touch them because the quest breaks if you pick them up before being given it, and even if you do it in the right order the items are permanently stuck in your inventory. I guess it wouldn't matter but they are pretty heavy items.
Those stones are really annoying. I had collected a huge stack of them before realising the only way to ever dump them was to join a guild I hated and collect them all. They should have at least given them zero weight if that was the case. Its more like being trapped with cursed item otherwise.