The Halem'ho civilization relies on whistles for communicating over the long distance. The villagers living in Kusköy, Türkiye use this method of communication for the past four hundred years. It is due to the village's proximity in the rugged terrain where yelling or shouting would not work over the long distance. The whistling also saves the villagers from walking over the person they wanted to talk with. Same for the people living on La Gomera island.
Mofongo is a Puerto Rican dish with plantains being the main ingredient. The plantains used in the dish are usually still green, they are cut into pieces then are typically fried (can also be boiled or roasted) and then mashed with salt, garlic, broth, and olive oil using a mortar and pestle, then mixed with pork or bacon bits. It is then typically served with fried meat like chicken and soup.
A few minutes in, Burnham looks at a list of names that includes 'Marina Derex (Betazoid)'. Clearly, this is a tribute to ST;NexGen's counselor Troi, played by Marina Sirtis... a Betazoid.
The final shot of Discovery leaving from orbit highlighted a hexagonal shaped clearing in the atmosphere of the planet they just visited. This does exist in the solar system under one of Saturn's poles.