Can I connect my Macbook (Retina, 12-inch, Early 2016) to my Macbook Pro (13-inch, Early 2011)?
As long as both Macs are in the same network this can be easily done.

To set it up do the following on both Macs


Open System Preferences -> Sharing
Enable Screen Sharing and File Sharing


Afterwards the remote Mac should get listed in any Finder window in the side bar (in the Network part). Click on it and either attach the drive or start screensharing.