In each sentence, underline the words that make up the compoound subject. Circle the conjuction that joins the subjects.
(I've underlined and circled using parentheses.)
1. An elederly man and a young family with two crying babies shared our table.
A: An elederly (man) (and) a young (family) with two crying (babies) shared our table.
2. My sister and I worried about Mama, for she wasn't strong and had recently been troubled with neuralgia, which could easily be aggravated by the cold.
A: My (sister) (and) (I) worried about Mama, for she wasn't strong and had recently been troubled with neuralgia, which could easily be aggravated by the cold.
3. An artist, my father's barber and his wife, a dentist and his wife, an elderly couple, a group of Kibei bachelors, and insurance salesman and his wife, and a widow with two daughters lived in our stable.
A: An (artist), my father's (barber) and his (wife), a (dentist) and his (wife), an elderly (couple), a group of Kibei (bachelors), and insurance (salesman) and his (wife), (and) a (widow) with two (daughters) lived in our stable.
1. babies is not part of the subject. It's in a prepositional phrase modifying family.
2. Don't forget all the other conjunctions.
The rest is correct. :-)