I need a way to be able to allow an admin user post an order comment when they update the order status that the owner of the order would then get posted on their order. This would both be viewable from the owner of the order, when the owner of the order was logged in under their order history view of that particular order, but would at the same time, get an email with these update comments. Ubercart 2 did this quite well. I imagine Drupal Commerce is capable, but how?
In Commerce this is not provided as a part of core. It is provided by the Commerce Message module. In addition to that, the Commerce Backoffice module provides an improved view that allows you to view a summary of an order (and send a message) directly from the order view.
Both are included in Commerce Kickstart, in case you want a quick demo.