With regards the IP address showing, this is already set with DNS
There is a DNS entry for each tenant, and the correct ssl, it is just the welcome email putting in the IP and not the FQD, so in the welcome email the correct FQD is showing under "Name of domain:" but under the "URL for logging in:" this shows the IP address and not the FQD
As for the password, so I do see what you are saying, but lets say they go and buy their own desk phone, how can they configure and set it up if they do not know the extension password? and again, if they click the url for logging in it presents them with the username and password so the username will be the extension, but who knows the password?