Using "it" to refer to a person in "The suspect is not... It is..."

Question

a. The suspect is not the man who was talking to John. It is the man sitting next to Sally.

b. The suspect is not the man who was talking to John. It is the person sitting next to Sally.

c. The suspect is not the man who was talking to John. It is whoever was in the room before they entered it.

Are the above sentences grammatically correct?

Could one replace 'it' with 'he' in (a)?

Could one replace "it" with 'he or she' in (b) and (c)?

Here, 'it' refers to a person. That's what bothers me.

Answer 1

You haven't really 100% firmly established "The suspect = the man sitting next to Sally" until after you say that - unless some context/conversation established that previously.

The suspect isn't a real person to investigators until investigation is performed and a firm identity is established. So you can use it until that is done.