First, choose a surname. Then, say if the number for the next name is 5, use the fifth letter of the surname to begin the next name. Continue this until you've got the whole family. I'm not sure if I've explained that very well, but I've included an example below and let me know if you have questions.
Surname: Kingston
DH: (3, 2)
Nathanael AinsleyDW: (4, 3)
September Paisley
DS/DD: (1, 5) Patterson
Edmund / (2, 8)
Desdemona NeveDD: (3, 4)
Viola LilithDS: (5, 2)
Tobias OliverDS: (5, 1)
Eliot EverardDD: (6, 3)
Rosalind Suri
Surname:
DH: 3, 2
DW: 4, 3
DS/DD: 1, 5 / 2, 8
DD: 3, 4
DS: 5, 2
DS: 5, 1
DD: 6, 3