A brother & a sister for each of the names on your short lists:
[name_f][/name_f][name_m]Alistair[/name_m][name_f][/name_f], [name_m]Phillip[/name_m], & [name_f]Gwendolyn[/name_f] – asa, pip, & dolly
[name_f][/name_f][name_m]Arthur[/name_m][name_f][/name_f], [name_m]Lewis[/name_m], & [name_f]Marion[/name_f] – art, lou, & mare
[name_f][/name_f][name_m]Barnaby[/name_m][name_f][/name_f], [name_m]Augustine[/name_m], & [name_f]Clementine[/name_f] – bee, gus, & clem
[name_f][/name_f][name_m]Benedict[/name_m][name_f][/name_f], [name_m]Percival[/name_m], & [name_f]Florence[/name_f] – ned, percy, & florrie
[name_f][/name_f][name_m]Earnest[/name_m][name_f][/name_f], [name_m]Franklin[/name_m], & [name_f]Margery[/name_f] – ernie, frank, & madge
[name_f][/name_f][name_m]Edward[/name_m][name_f][/name_f], [name_m]William[/name_m], & [name_f]Alexandra[/name_f] – teddy, wilkes, & sasha
[name_f][/name_f][name_m]George[/name_m][name_f][/name_f], [name_m]Walter[/name_m], & [name_f]Frances[/name_f] – georgie, walt, & fran
[name_f][/name_f][name_f]Hazel[/name_f][name_f][/name_f], [name_m]Newt[/name_m], & [name_f]Pippa[/name_f] – hal, newt, & pip
[name_f][/name_f][name_m]Henry[/name_m][name_f][/name_f], [name_m]Peter[/name_m], & [name_f]Beatrice[/name_f] – hank, pete, & betty
[name_f][/name_f][name_m]Otto[/name_m][name_f][/name_f], [name_m]Morris[/name_m], & [name_f]Hilda[/name_f]
[name_f][/name_f][name_m]Phineas[/name_m][name_f][/name_f], [name_m]Thaddeus[/name_m], & [name_f]Marceline[/name_f] – fin, tad, & marcy
[name_f][/name_f][name_m]Rupert[/name_m][name_f][/name_f], [name_m]Whitman[/name_m], & [name_f]Gretchen[/name_f] – rueby, whit, & greta
[name_f][/name_f][name_m]Theodore[/name_m][name_f][/name_f], [name_m]Benjamin[/name_m], & [name_f]Josephine[/name_f] – teddy, jem, & posey
[name_f]Agatha[/name_f][name_f][/name_f], [name_f]Prudence[/name_f], & [name_m]Thackeray[/name_m] – aggie, pru, & ray
[name_f][/name_f][name_f]Agnes[/name_f][name_f][/name_f], [name_f]Mildred[/name_f], & [name_m]Clyde[/name_m] – aggie, millie, & clyde
[name_f][/name_f][name_f]Beatrix[/name_f][name_f][/name_f], [name_f]Lucinda[/name_f], & [name_m]Robin[/name_m] – bee, lu, & ro
[name_f][/name_f][name_f]Clementine[/name_f][name_f][/name_f], [name_f]Marigold[/name_f], & [name_m]Tobias[/name_m] – clem, goldie, & toby
[name_f][/name_f][name_f]Frances[/name_f][name_f][/name_f], [name_f]Leona[/name_f], & [name_m]Arthur[/name_m] – frankie, leo & artie
[name_f][/name_f][name_f]Harriet[/name_f][name_f][/name_f], [name_f]Roberta[/name_f], & [name_m]Linus[/name_m]
[name_f][/name_f][name_f]June[/name_f][name_f][/name_f], [name_f]Clara[/name_f], & [name_m]Abel[/name_m]
[name_f][/name_f][name_f]Louisa[/name_f][name_f][/name_f], [name_f]Alice[/name_f], & [name_m]Peter[/name_m] – lou, lissy, & pete
[name_f][/name_f][name_f]Prudence[/name_f][name_f][/name_f], [name_f]Geraldine[/name_f], & [name_m]Alfred[/name_m] – pru, gerry, & al
[name_f][/name_f][name_f]Ramona[/name_f][name_f][/name_f], [name_f]Cornelia[/name_f], & [name_m]Sidney[/name_m] – mo, cory, & sid
[name_f][/name_f][name_f]Sybil[/name_f][name_f][/name_f], [name_f]Verity[/name_f], & [name_m]Maxwell[/name_m]
[name_f][/name_f][name_f]Tabitha[/name_f][name_f][/name_f], [name_f]Imogen[/name_f], & [name_m]Felix[/name_m] – beth, meg, & felix
[name_f][/name_f][name_f]Winifred[/name_f][name_f][/name_f], [name_f]Susannah[/name_f], & [name_m]Gilbert[/name_m] – winnie, susie, & bertie