As others have said the Yovra is going to be the biggest challenge. Sucks that Shadow gorget needs 2. In my LS everyone needs one for their gorget...
I just recently did this quest so I can give some tips on the organ farming maybe.
I basically organized an organ farming/skill up group. I tried to get everyone (who could) to sub ninja so that People(mages) could spend more time skilling up and less time healing.
We camped at the west tower. There are a lot of the higher level Hpemde and they seem to drop organs better than their lower level counterparts. Also, I think we were able to get the higher level Phuabo they would pretty often drop 2 organs at once. We had thf in the party. I was told by someone TH didn't have an impact on organ drops but I don't know if they were messing with me because I felt it did. Also, I am not sure why, but the lower level Xzomits seemed to drop organs better than the higher level single ones. (only the head of the 'family' dropped organs for us)
I was able to farm all the organs I needed in one day like this, people got skill ups and everyone got a little experience. Note: I got an Obi even though I didn't need it just so I could get Virtue Stones, so I didn't need a Yorva
~ Happy hunting!