All the things you said are already included in my suggestions. They are essential to make this tavern system work.
Well not explicitly, hehe. You wrote that taverns should offer food, armor, etc., which is fine, but I really think that these goods should also be offered also by specialized, unique structures (not tavern-shaped structures), like marketplaces or armories, that work the same way that you have proposed. These new buildings would obviously have a different aesthetic design more suited to their individual uses. Ie. a market would consist of stands and stalls. This would help make cities in life is feudal look a little more diversified.