Have you checked Celigo’s help center? Not sure exactly what you’re looking for. Getting Celigo connected to NetSuite is pretty straightforward.

https://docs.celigo.com/hc/en-us/sections/360010950292

Yes, you can import employee records including password and role(s).

You can’t create an address independent from a customer record. How about creating a custom list for these sites? This would resolve the free-form text issue and allow you to report and search on the sites using a saved search.