Great to see Ron Glass (Shepherd Book from Firefly) in this latest venture from Whedon, I’m glad he had more than a brief cameo in the first episode.
Dr Streiten was a high ranking medical officer within SHIELD, with clearance of at least level 7. When Coulson confronted him about the operation that brought him back to life he said that Fury had brought him in to assist and that he thought the procedure was morally wrong.
Dr Streiten’s whereabouts are currently unknown.
As far as I know he has no analogue in the comics, drop a comment if I’m wrong.