You keep mentioning design meetings as a source of technical insight that a person can co-opt as their own expertise. If you steer your interview questions more

You keep mentioning design meetings as a source of technical insight that a person can co-opt as their own expertise. If you steer your interview questions more towards things that are 'solo' in nature then you might have a better job of identifying people that have more software development experience. An example of such a question could be ... can you tell me about a time that you tracked down a bug that you at first thought was not possible but later identified and found a solution for?