Prior to joining the Bard's College, I held a number of quest items in inventory: Panea's Flute, Finn's Lute and Rjorn's Drum.

You can not gain these quests until you join the College.

Once I joined the college, I was able to tell some characters that I have their item (Finn's Lute), but they don't actually take the item, and you can't get the quest.

I WAS able to get the quest for Panea's Flute, but already had the item and couldn't give it to the NPC nor could I actually make the quest active, even though it shows in the available (not completed) Quest list.

Sounds like a bug to me.

A bit irritating as they occupy valuable weight in my inventory and I'd really like to get rid of those items.

Regards
LK

The good thing is even though it says it has weight if its flagged as a quest item its weightless. Hopefully this issue will get fixed soon (quite common to see happen)