What is this 某 doing after the names?
It indicates that the given name is unknown or intentionally hidden. 'A certain Chen/Liu', 'a Mr. Chen/Liu', 'a Ms. Chen/Liu', etc. 

In the case of women 氏 can be used, or was used historically, when only her maiden family name was recorded, e.g. Mao Zedong's paternal grandmother is quoted in Wikipedia as 罗氏, which simply means 'née Luo'.