Captain Durango is the first Tellarite to be seen on screen since Terra Prime (2005), who appears to have the appearance of other Tellarites of that era.
In this episode, it's mentioned the ship being towed by the U.S.S. Cerritos and Merced contains a mysterious "molecular fluid that generates life from inorganic material." This is a nod to Star Trek II: The Wrath of Khan (1982) & Star Trek III: The Search for Spock (1984) in which Federation scientists Carol and David Marcus develop a device called the Genesis Torpedo that if detonated, had the capability of generating life on an inorganic surface such as a dead moon.
Boimler blames an overheard threat on a holodeck program involving Moriarty, the villain from the Sherlock Holmes short story "The Final Problem." A holodeck version of Moriarty was the antagonist in two episodes of TNG: Elementary, Dear Data (1988) & Ship in a Bottle (1993).
The USS Merced is the second California-class ship seen in the series and, like the Cerritos, is named for a city in California. It is not identical to the Cerritos, as its hull features heavy blue markings, indicating its primary function is science/medical. The Cerritos' yellow hull markings would therefor seem to indicate operations/engineering/security specialty. The Merced's bridge is a recolor of the Cerritos's, with a darker lighting scheme and purple on the command chairs.