Agreed, it is important that you get to the root of his issues with eating. I suggest a vet visit to check teeth, and if you have any baby gas drops I’d go ahead and give some just in case it is gas. How long has he not been eating and does he still produce poops?
As for the veggies, I respectfully think that it’s a bit overboard. Guineas (if I’m not mistaken) can have unlimited veg, but rabbits it is recommended to give 1cup per 2lbs of body weight.
As A&B already said, take it easy with the cabbage, kale, bok choy and parsley. Can you not get a hold or romaine? It’s a staple veg for many people because it’s not gassy and isn’t high in oxalates like spinach.
I’d recommend giving romaine daily, and you can alternate some add-ins such as kale, bok choy, and cabbage. If you really want to give all three, I’d say give them no more than every OTHER day, since they carry the risk of gas production. Parsley, broccoli and bell pepper I would say 2-3x a week, and carrots, banana, and apple should also be only 2-3x week due to sugars.
If you’re looking to add variety and something that you can grow, I recommend an herb garden. I have basil, mint, oregano, rosemary, lavender, and sage that I mix in with hay and flowers to make “forage” or I just give as a treat.