I couldn't find any other information for this. I have a Race mod in the works, and I want to be able to equip both Argonian and Khajiit tails at will. But the race I am using does not have tails by default, so the Ring that I made that equips to the tail slot only is visible on Argonian and Khajiit. I do not want to use an invisible tail of sorts, as I do not want an invisible tail showing up with Detect Life. What ways could I try to fix this?

I don't think you can 'fix tail showing up with detect life', because the equippable tail needs to be rigged to tail bone or something(though it doesn't need to be if you want it to be unmoving decoration), and detect life effect reflects what the skeleton is like.