Which fields are pulled from CB & J3 into address?

I noticed that if no address is specified and a user is asked for an address, that the default name on the address is pulled from the CB "Name" field. For example, if the CB field name is 2 words "Joe Smith", when I go to checkout and the address form pops up, the 'First Name' default value is 'Joe' and the 'Last Name' is 'Smith'.

Are there any other fields that I can set up on the CB profile that Hika will pull from the CB profile? e.g. address, postal code etc.?

No there is no option to do that.

Then how does the address form pick up those 2 fields?

The system in HikaShop automatically takes the name from the name field of Joomla. It doesn't rely on CB's information.
You can find that specific code in the function form of the file components/com_hikashop/views/address/view.html.php