Customer Portal quetions

Customer Portal quetions

I'm investigating for use by an organization where I volunteer:
  1. I'm assuming I can parse data by customer so that multiple customers using the customer portal can't access each other's information.  Correct?
  2. Can the survey feature be used within the customer portal?  Meaning that surveys are presented, responses are captured, results are displayed all within the customer portal.
  3. Is the customer portal branded with my company name/logo, or zoho? 
  4. Can I use my own domain for the customer portal?
Thanks