idk about the others, but the critical one, well... actually there are some types of people who are not really interested or know how to really do the job of leading anything but they live and I emphasize this, they live to criticize others in place of leadership and/or authority. No matter where you go you will find a few like this. They are the types of people that if you say "would you like to do the job?" they will typically decline but then only if they can continue to criticize.

The one way to defuse this type of behavior is to let yourself be unaffected by it. Short replies to their criticisms, like "thank you for your input... " stop. Just that, nothing more. don't give them a retort or reply to their opinions and don't give them anything to continue, argue or any idea of whether you agree or disagree. Their fuel is disagreement and opposition. Don't give that to them and eventually they will either give up or at worst they will continue but it will be minimized by your lack of response other than "thank you for your opinion." and nothing more. Hard to keep going when there is no bite.

Hope this helps.