Thanks for posting the file however im afraid adding arisha.txt to my save folder did not help.I always remove the horns and wings but...
I dont have any other saves prior to completing her mission and before she disappeared.
I opened my global.txt file via notepad++ and I saw the companions list entry. I tried to add Arisha to that entry but that renders the save corrupted or the savefile opens but all my other companions are gone. I am noticing a lot of NULL characters, not sure if this is because of notepad++ or some other problem. I posted a picture of it, can you post a photo of your global.txt for comparison?