UPDATE: Just called DL and the agent said that the manual says that there should be at least an 180 mins connection time from a DL-operated flight to a non-DL international flight. Despite this, she went to consult a supervisor and came back to tell me that I'd be "perfectly fine" and that the connection time was "more than sufficient." She even went further to tell me, "I sell these tickets all the time and no one ever complains." Although I appreciate her reassurances, I'm not really reassured by her, especially after she consulted her manual (or whatever it is).