Congrats on writing posting your first article!! I think it's a pretty good first article. There are a few points I'd like to clarify just to make sure the readers are clear.

Mirroring is not supported on different Editions for the Principal and Mirror. Though possible to do so, you lose supportability by using different Editions.

The service accounts for the SQL services should not be running as domain admins ... ever.

The principal and mirror servers do not need to use the same port number on both sides. In fact, there are some circumstances where this isn't even possible.

The role of the endpoint doesn't have to be the same on mirror and principal. Each one has to be in either the "Partner" or "All" role.

The picture at the end does not show that the service account has been granted Connect permissions. In fact, it doesn't show the mirroring endpoint at all. The reason for this is because the service account's permissions are inherited from it's role as sysadmin rather than having been explicitly granted.

Regards,