Oh wow, I'm sorry you can't have any tomatoes! That's a tough one, but I'm sure you can still make it work. I'd probably add some bell peppers maybe to make up for some of the bulk and just add a little extra broth or water to make sure you have enough fluid. I like pureed pumpkin in soups, too, to add some creaminess.

My sister can't eat onions or garlic, so if I were making it for her I would use chopped fresh fennel instead of onion. Let me know if you figure out some good swaps!