Cassie fights Lillian Jean to get respect from her and to show that she isn't a slave and to get back at her for the strawberry incident about a month ago. Cassie tricked Lillian Jean to gain her trust so she can blackmail Lillian Jean so she can not talk about Cassie fighting her.
Papa is shot by the Wallace's is revenge for Mamma trying to boycott the Wallace store show that the Wallace's are vengeful and that they will seek revenge to anyone that try's to oppose them. The Wallace's know that they can get away with crimes because they are white and that makes them "Superior."
Papa talks about selling some farm animals and to conserve making food and to make just enough for the family until he could get back to working on the railroad shows how desperate he is to not sell the land that Grandpa had work so hard for. Papa is determined not to sell the land to Mr. Granger even though he and his family are in a financial trouble.