Personally, I think the 'impact' question is completely valid and not even remotely cocky. It's important to avoid structuring the question in a way that sounds like "what's the impact of not hiring
me" and make it clear you're interested in hearing about what's important for the business. It shows commercial awareness which is usually quite lacking in technical interviews.
As for feedback, unfortunately most companies fail to offer useful feedback if you aren't successful in getting the job as you're no longer considered to be of any importance to the business. Some companies have policies that prevent them from giving you too much detail and some simply refuse in order to avoid opening up a legal can of worms. One seemingly harmless question that you could ask after you get rejected is "What one thing should I work on to improve my chances of working for your company in future?". Take the advice and address it in your next interview with the next company.