HUF Formation queries

Hi All,

I have been married since 2016 and would like to apply for PAN for HUF now (2022). The HUF will be currently having me and my wife as members. Kindly answer below queries :

1) What are the documents required for applying a PAN for HUF? Is a HUF deed required? Or only Marriage certificate and Marriage affidavit is enough?

2) What will be incorporation date of HUF? Can it be from 2016 (1 day after date of marriage) or current date? What are tax implications of Backdated incorporation?

3) Can HUF be formed with 0 corpus amount? 

Thank you in advance fr your time