Anton Ivanov shows Dr. Radcliffe a copy of Agent Coulson's obituary. The death date is listed as May 4, 2012 - the American wide release date of The Avengers (2012).
When the Radcliffe LMD is acting "possessed" he says "Amicitiae nostrae memoriam spero sempiternam fore. Vir sapit qui pauca loquitur. Alea iacta est," which is Latin and translates to "I hope that our friendship will be everlasting. It is a wise person who talks little . The die is cast."
Sam mentioned Red Dawn (1984), which features Clark Gregg's at-the-time wife Jennifer Grey. Adrianne Palicki appeared in Red Dawn (2012) with Chris Hemsworth.
This is the second episode in which Melinda May doesn't appear after Laws of Nature (2015); although Ming-Na Wen portrayed her Life-Model Decoy.