Big Al's philosophy about farming being "the worst mistake in the history of the human race" is not the ranting of the deranged mind of a homeless man. It actually comes from a 1987 paper of the same name by noted American scientist Jared Diamond and makes the case that modern ills such as pandemics, war, sexism, and social stratification among other things can all be traced back to humanity's adoption of agriculture.
Al gives Danny a sandwich from "the deli on Bleecker." Bleecker Street is where the New York Sanctum Sanctorum is located in Doctor Strange (2016).
Danny asks Colleen if she had ever thought of teaching kung fu at her dojo. Marvel developed the Iron Fist storyline after the success of Kung Fu (1972).