Thinking of setting up a HHA.

I have a few questions about booking Reward Saver Flights.

Do all members have to have had activity during the previous 12 months?

Can RSF be booked for people on the friends list?

Is activity carried over to the household account from the individual accounts or has to start from the forming of an HHA?

One other question Is the HHA instantly available to use or does it take upto 14 days to become active like an Avios.com account?

Many thanks