For example, resumes are not uniform so not all the same kinds of information may be available for all candidates. Tailor the questions to the CV and the information available, try to be consistent, but evaluate. Cannot ask about ethnicity. Re Affirmative Action or discrimination it is our perception of the candidate that is most important. Remember that language should be gender neutral and appropriate.
Unlawful questions Remember that interview starts with email, phone or when the plane lands.
There is no time that is exempt from proper behavior. Questions and indirect questions to be avoided. What this does mean is that not all the same things are going to be discussed with each and every candidate. There is no way around this, short of something so impersonal and rigid that it defeats the purpose of the interview.