You might expect some problems with combinations of different foods because some people are just sensitive to different stuff. For example, my mom can't eat minced meat and cucumbers in close proximity. Also you might be sensitive to one type of onions/garlics/whatever. Sensitive = will give you a huge case of the poops
However, I'm a person less than half your weight who doesn't eat all that much, so my idea of huge poops might be your regular morning load.
Speaking of the psychological side, I had this thing when I was a kid: I ate very slowly and very little and I was extremely picky about food and my family got annoyed with me to the point of actually shoving food into my mouth. When I became a vegetarian, I had this problem because I didn't eat many different kinds of vegetables (I don't eat fruits besides apples either, but they aren't as important to me). I immediately decided to try the "least icky" stuff on my list (rice, tomatoes and mushrooms) but I still can't eat beans and peas and similar, which I'd really need in order to boost my protein intake, nuts are crazy expensive here and I can't eat that much dairy every day. I have this exact same kind of mental blockade with the remaining stuff that you describe, down to the T. So if you get any good tips that work, follow up in this thread, I'd really like to know.
edit: the things I've begun to eat were my "auxiliary" dislikes, I found out that I just disliked certain ways of prep or different kinds. so maybe, when you find you actually like some of them in liquid forms, try to follow up with them roasted and spicy or combined with your other fave foods. When I started eating pure tomato sauce with cheese, then standalone, then tomato juice, I knew that eating raw tomatoes (first spiced up and combined with cheese and lettuce, then standalone) was a no-brainer. It's gonna happen for you, but with a lot of trial and error.