Former guy here who was also weird about eating amd underweight. I'm about to leave so I didn't have time to read your entire post. But about your lack of appetite, I have the same thing. Although when I was underweight I didn't. But right now I do. I get nauseated quickly when I eat "too much". I don't know if you have the same thing. You have to try finding something that doesn't fill you up a lot. Maybe cheese, nuts or (stevia sweetener chocolate) milk. Also, what helps to stimulate my appetite is tea. Also fasting works for me. Not too long though, about 14 hours or so, to make myself really hungry and I can usually eat a lot after that
I'ma eat this beat like a beef eatin vegan