Brother I would sincerely suggest to go to Excise Office, Lahore directly, and get everything done by your own self. Do not involve any agent, etc. In all this.
If biometric verification, physical presence of current owner, etc. Is compulsory and mandatory, then also manage to have current vehicle owner with you too, when you visit the office. Request him to spare some time and accompany you to office, and have all the docs, book, card, etc. Ready and with you.
Do ask for No. Plates too! (From the current owner as well as Excise Office)