what do you think of some of the tangential characters Wang lung's father uncle, old mistress and uncle wife? Do you find it curious that none of them have names?

No, I don't find it curious that they weren't named because their importance to the novel is like that of furniture in a house. All of these tangential characters play off of Wang Lung; they are the reason we know (or think we know) who Wang Lung is and why he acts the way he acts..... in some cases they are the cause and effect......