Is it normal to ask clarification questions?

Being an RN - definitely normal to ask for clarification. You never assume anything with a patient's health and/or treatment.

Generally, yes. A lot of the time that people get upset for asking such questions is because they don't actually know the answers to what you are asking. That can cause some people to get defensive and they lash out.

Yes. I’d rather someone ask than not ask and do something wrong

Always do. Even if you doesn't even respect the person nor the thing to do. All to do with doing it correctly

For me it is. For some sour and bitter people, no.