The oath may be taken before the President, the Vice-President, the Secretary of Defense, any commissioned officer, or any other person designated under regulations prescribed by the Secretary of Defense. Active duty, reserve, guard or retired commissioned officers of the US Armed Forces may administer the oath. Officers who resigned their commissions, and were transferred to the Obligated Reserve Section (ORS) or the Non-affiliated Reserve Section (NARS), may not administer the oath. (Exception: Commissioned warrant officers in the grade of CW2, CW3 and CW4 may also administer the oath).
yes
Commissioned Officer status is not rescinded upon retirement. It is a "transfer" to the Retired Reserves and the officer can still be called back to active duty.
No.
Technically an Officer Candidate outranks every enlisted rank. However, they are not officers and you do not salute them. In some situations on a post if the Officer Candidate School trainers deem it necessary, they may make passerby's salute the candidates if they are being disrespectful. This really depends on the SOP of the post, but in general the answer is no.
retired as a senior chief petty officer
no
No, there is no requirement to salute a retired officer. If a lower ranking person wants to salute a retired officer as a sign of respect, that would be appropriate. However, it is not required by regulation.
In speaking to the officer you would address them by their rank and name. In writing to the person you would follow the rank with the word "Retired" or "Ret."
Yes they can.
Police Officer
Use the military rank.
Certainly. There is no law against retired persons going back to work.
You ask the police officer, or they would've turned in their badge,you would see them without a badge.