For family:Source (e.g. 1861 Census Return)Contact (i.e. Address, and permanent, and "from" date based on census year)Ability to add family member (as family wizard)For each individual:Source (again)Birthplace, Birth DateOccupation (inc start date based on census year)
Also possibly a DB enhancement:Age at time of census (a new field)Marital Status at time of census (a new field)