> Then I realized that it wasn't totally clear to me what json_list_to_str_vector() should do, exactly, and so I don't even know how it would compare.

It just converts a JSON-encoded list of strings into a Vec<String> doesn't it? That's what the other languages do:

* get data from some envvar

* decode it from json to an array/list/vector of strings

* concatenate argv[1..]to the result of (2)

* execute this new argslist (the first item being the name of the program)