It is not possible to reply to some of your questions without knowing the full facts of the case and without actually seeing the documents. However, let me reply to whatever questions can be answered.
“Zero FIR” or the FIR with Zero number is generally registered when the complaint is received in a police station which does not have jurisdiction to entertain that complaint and the FIR is to be sent to the regular police station which has jurisdiction for registering the regular FIR.
It is desirable that the complainant / informant should sign the FIR format (specially where the complaint is given verbally). However, sometimes a separate signed complaint is given (on a plain paper or a letterhead) by the informant / complainant which is then reproduced in the FIR format verbatim; in such case the absence of complainant’s signature on the FIR format may not be material, since the real first information is the one given by him by his separately signed complaint.
Yes, a computer-generated FIR may be legally valid, more so when it is accompanied by the certificate under Section 65-B of the Evidence Act.
There is no prohibition in the Criminal Procedure Code for the trap laying officer to register the FIR himself, though there is a practice in some anti-corruption agencies to give the subsequent investigation to some other officer.
For your other questions, in particular the question whether in your case the FIR can be challenged, please show your documents to a local lawyer and obtain his considered opinion.
Dr. Ashok Dhamija is a New Delhi based Supreme Court Advocate and author of law books. Read more about him by clicking here. List of his Forum Replies. List of his other articles. List of his Quora Answers. List of his YouTube Videos.