My father in law is a faddy so and so. He'll eat no vegetables apart from sprouts and processed peas. He's never eaten cheese, rice, pasta, anything containing tomatoes and if he goes out to eat he'll only eat a burger or steak and chips. Cooking for him is a challenge indeed
I think of faddy as meaning the latest trend in food, such as avocados on toast were recently.
Fussy eaters aren't necessarily faddy. They're a pain, if you have to cook for them. I'll keep making very hot chilli and curry or something else they won't eat, until they get the hint and sort their own food out.