IMO Ogre Bone is definitely worth feeding to a slimeogre bone, the agi loss hurts a lot but in some niche builds this item makes sense.
avian feather, this is a strictly worse slimy fluid (which is also kinda abundant) as LUCK is clearly trash. This is one of the last ones I use for my slime and never for aura. At least, it is useful for a quest and even 2 agi item is « ok »
Avian Feather and Luck I think you're wrong about, but to be fair it does take two things to make it good.
First, you need to read the book that turns your Lewd Knowledge into MATK.
Second, you need to use that one mental change machine to transfer your Luck into Lewd Knowledge.
Luck being the least useful stat makes it a prime candidate for reduction, and using that machine repeatedly also helps with corruption management.