I am installing a 400A. Service which will split into 2-200A panels. One will service a workshop and another will service our home. Each will have a service disconnect prior to the individual panels. The home has a 18kW backup generator. My questions are: How are the neutrals and grounds to be connected from the meter socket to the disconnects? Are they to be bonded at one point? Once they (the neutrals & grounds) leave the disconnects and continue to the panels are the neutrals and grounds to be isolated at the panels? Should I install ground-rods for the panels? Does the neutral and the ground from the backup generator need to be isolated from each other at the panel that supplies the home?

Where does the transfer switch figure in?

Planning on backing up the garage?

Is the garage detached?