I agree with your general read of Kidney deficiency, and stopping the Loranthus in case it's aromatics are damaging Sophie's Yin
My first thought is to try Yi Guan Jian. It may potentially help with the inappetance (allowing the cat to generate Yin from food more effectively) as well as the lip smacking (which can indicate either dry mouth or nausea, both of which YGJ can address).
The photosensitivity is associated with Blood deficiency, so using a stronger Blood tonic is indicated. Yi Guan Jian provides that, whereas her previous regimen includes only a little Blood tonifying action in the Loranthus. Yi Guan Jian should do a good job of addressing the renal failure, too, as well as the vomiting.
Hopefully, if she gets to feeling stronger and more herself, her insecurity (manifesting as yowling for the owner) will subside.
Hope this helps you out!