A further thought, as to 'meatiness'. Bean soups, and lentil soups, are excellent flavoured with pimenton. It adds a background smoky richness that a guest might assume came from bacon or pancetta. Keep everything very simple. A base of onions cooked until sweet, in olive oil, and then add tomato, water, your beans, and your most flavoursome oil to finish.
The best herbs might be rosemary, or a little thyme, or just flat leaf parsley.
ps. Marna, I am sorry, I have just noticed that you have already mentioned smoke paprika, but a modest amount, and the gentle slow simmering of these sort of soups, mean that the flavour softens considerably. A careful hand is needed, I agree, but it is far more useful than you suggest.
But not in a classical French onion soup, please. If you have cooked your onions properly, then a vegetable stock will work. It might not be quite correct, but it will be nice.
It's probably best to look to context and tradition, when using spices. Not out of pedantry, but simple because time, custom, and place usually provide the best starting point, and the most relevant base for your own experiments.