I think [name_f]Frances[/name_f], [name_f]Josephine[/name_f], and [name_f]Lily[/name_f] make a really sweet sister combo. For twins, [name_f]Lily[/name_f] & [name_f]Jade[/name_f] (both 4 letters and word/nature names) and [name_f]Lily[/name_f] & [name_f]Olivia[/name_f] (both have the li sound) would also work well together too.
[name_f]Jennifer[/name_f] was a very popular name in the early 80s, so I would go with that one for the mom. For the dad, I would do either [name_m]William[/name_m] or [name_m]Joseph[/name_m], those sound like very fatherly names. For the older girl, I like [name_f]Kathryn[/name_f] or [name_f]Isabelle[/name_f], and for the twins, either [name_f]Lily[/name_f] and [name_f]Jade[/name_f] or [name_f]Josephine[/name_f] and [name_f]Olivia[/name_f]. If the dad’s name is [name_m]Joseph[/name_m], [name_f]Josephine[/name_f] and [name_f]Olivia[/name_f] would be cute because it’s like the daughter is her father’s namesake. [name_f]Hope[/name_f] this helps.