Is the answer given wrong ?!

#1

shouldnt the answer be N-1 as there will be at last only 2 remaining.and after asking the second last person we need not to ask the last person…
so actually we gonna asked to n-1 persons…please correct me if i am wrong or missing something here !!!

#2

The total number of people is N+1 and not N. It is N-1, but replace N by (N+1); so answer is N.

#3

They haven’t considered the case where the people have on themselves so that we don’t ask a person his/her own name.

#4

I think is covered because it states

and you know the persons by name

so you won’t be asking a person its own name