If you are installing this in the cloud you need to determine what the base URL is supposed to be (i.e. how would you access your MHN server via a web browser after it is setup). Do you have an IP or a domain name associated with your MHN server? You would enter this IP/Domain for the server base URL and just replace "1.2.3.4".
The email related inputs above are only used for password resets. They are not strictly necessary if you have admin control of the MHN server.
Answers to Questions:
1. I assume you can now make it through the MHN server install after following what I stated above.
2. yes, you need other servers to deploy honeypots on. We highly recommend not to run the MHN server software on the same machine as the honeypot. I would recommend Ubuntu 12 or 14 for the honeypots.
3. Yes, if you deploy a handful of honeypots you should start getting thousands of events per day.
I hope this helps.
--Jason