I used to consider these exercises, and actually did them in the 90's when I was a news photographer. I would 'limit' myself either in the day or the week, and try to do all my regular assignments with my choices, but I usually had access to other gear at the office. I found either a 35 and a 300 or a 28 and a 135. Most of the week's work consisted of the 'grip and grin' style of shooting so the 28 or 35 would be a solid choice over a 50 since those assignments often had 5-8+people in frame. The longer lens choice would mostly cover the sports which was always a potion of the week, with the 135 for the indoor sport season and 300 for the outdoor, with the added coverage of a fast 135 for nice portraits or candids. The fast 300 could do the indoor sports and also was excellent as a candid or 'wild art' collection lens.
I considered these exercises valuable, since the choices would form the core of gear I would pack normally. The bag would always have at least one flash, perhaps another back-up body or a body dedicated to the longer lens(s), several old 100ft cans holding 8-10 rolls of mostly B&W, one or two filters. I would round out the lens selection with a light 50mm 1.8, and usually a 24mm which was my standard wide angle, with perhaps a fast 85 instead of the 135mm, or even a fast 400mm with converters for the longer distance sports coverage.