To connect to an enterprise SDE database:
1. Insert Tab > Connections > New Database Connection
2. Project tab on the right side of screen shows Maps, Toolboxes, Databases, Styles, Folders. Expand Databases--you should see your connection named with the instance that was used. Here's where you can rename the connection if needed. (We couldn't rename these connections in the early beta versions.)
With Pro 1.0 (not the pre-release) I can bring in high resolution photography (3 inch) from an SDE database without any hitches. Yay!