Thanks for the detailed review!
Fixed most issues raised by Ashish and Hari.
1) any hostname that resolves is valid for zookeeper and broker. I didn't include FQD for brevity and clarity
2) I'd rather not document properties that we don't want users to override.
Lets view it as internal implementation detail? I feel that documenting invites fiddling, and I'd rather they won't fiddle here.