First of all it is my opinion that neither the ceremony and/or the questions are necessary. God calls the man.
However, it is something that is desirable because Church leadership must protect the flock from the wolves in sheep's clothing.
In my own case it was done privately. I had been the Assistant to the Pastor of the local Church where I was for quite a bit of time.
The Church membership wanted it, the elders (it was a Baptist Church that had elders as well as deacons) wanted it. I agreed but I didn't want it to be public.
There were only a couple of questions because they all knew me.
It was announced to the Church later.
I don't know if it's an urban (church-style) legend or not but when Spurgeon was asked why he didn't want to be ordained he replied "I don't want anyone's empty hands on my empty head".
Anyway the essentials IMO are :
Affirmation of salvation with the candidate's testimony.
Affirmation of the doctrine of the Trinity with a further discussion of the meaning of "the Word became Flesh".
Affirmation of salvation by grace through faith apart from works.
Affirmation of the inspiration and infalliblility of the written Word of God.
Affirmation of OSAS.
Affirmation that God has called the candidate to preach the Gospel.
Affirmation of seeking purity of life.
There are many other qualifiers and I am sure that some will find this list wholly inadequate. It is merely my own opinion. These are at very least essential.
In reality there is probably no adequate list.
Typing in "baptist ordination questions" gives 207,000 links in a GOOGLE search.
NAS 1 Timothy 5:22 Do not lay hands upon anyone too hastily and thus share responsibility for the sins of others; keep yourself free from sin.