We are a month into “casually” trying for number four and I was just in need of an excuse to get active here on NB again! 
What would you name a brother or sister to [name_m]Peter[/name_m] ([name_u]Pat[/name_u]), [name_f]Sabina[/name_f] ([name_f]Bina[/name_f]) and [name_f]Dorothy[/name_f] ([name_f]Dora[/name_f])? Middle names in the style of Nightingale, Wildrose and Mayflower.
You have quite a mix there!
[name_f]Mabel[/name_f]
[name_f]Anastasia[/name_f]
[name_f]Thalia[/name_f]
[name_f]Elaina[/name_f]
[name_f]Rosalie[/name_f]
[name_m]Walter[/name_m]
[name_m]Harold[/name_m]
[name_m]Jack[/name_m]
[name_u]Drew[/name_u]/[name_m]Andrew[/name_m]
[name_m]Callum[/name_m]
[name_m]Otis[/name_m]
[name_m]Peter[/name_m], [name_f]Sabina[/name_f], [name_f]Dorothy[/name_f] and
[name_u]Wallace[/name_u]
[name_m]Karl[/name_m]
[name_m]Emil[/name_m]
[name_m]Oscar[/name_m]
[name_u]Tristan[/name_u]
[name_m]Edmund[/name_m]
or
[name_f]Anastasia[/name_f]
[name_f]Djuna[/name_f]
[name_f]Callista[/name_f]
[name_f]Emmeline[/name_f]
[name_f]Lucy[/name_f]
[name_f]Lucina[/name_f]
[name_f]Winifred[/name_f]
[name_f]Georgina[/name_f]
[name_m]Peter[/name_m] ([name_u]Pat[/name_u]), [name_f]Sabina[/name_f] ([name_f]Bina[/name_f]), [name_f]Dorothy[/name_f] ([name_f]Dora[/name_f]) &
[name_f]Amelia[/name_f] ([name_f]Mila[/name_f], [name_f]Mia[/name_f], [name_f]Millie[/name_f])
[name_f]Annabel[/name_f] ([name_f]Annie[/name_f], [name_u]Billie[/name_u], [name_f]Belle[/name_f])
[name_f]Lenora[/name_f] ([name_f]Lena[/name_f], [name_f]Nora[/name_f])
[name_f]Beatrice[/name_f] ([name_f]Bea[/name_f], [name_f]Betty[/name_f], [name_u]Tris[/name_u])
[name_f]Harriet[/name_f] ([name_f]Hattie[/name_f])
[name_f]Ophelia[/name_f] ([name_f]Opal[/name_f])
[name_f]Willa[/name_f]/[name_f]Wilhelmina[/name_f] ([name_f]Minnie[/name_f])
[name_f]Georgiana[/name_f] ([name_f]Gigi[/name_f], [name_u]Georgie[/name_u], [name_f]Annie[/name_f], [name_f]Ana[/name_f])
[name_f]Edith[/name_f], [name_f]Edwina[/name_f] ([name_f]Edie[/name_f], [name_f]Winnie[/name_f])
[name_m]Quentin[/name_m] ([name_u]Quinn[/name_u])
[name_m]Frederick[/name_m]/[name_m]Wilfred[/name_m] ([name_u]Freddie[/name_u], [name_m]Will[/name_m])
[name_u]Elliott[/name_u], [name_u]Elias[/name_u] ([name_m]Eli[/name_m])
[name_m]Henry[/name_m] ([name_m]Hawk[/name_m])
[name_m]Oliver[/name_m] ([name_u]Ollie[/name_u])
[name_m]Percival[/name_m] ([name_u]Percy[/name_u])
[name_m]Alexander[/name_m] ([name_m]Alec[/name_m], [name_u]Sasha[/name_u])
[name_m]Roland[/name_m]/[name_m]Ronald[/name_m] ([name_u]Ronny[/name_u])
[name_m]Felix[/name_m]
[name_m]Charles[/name_m] ([name_m]Chuck[/name_m], [name_u]Charlie[/name_u])
[name_m]Jasper[/name_m] ([name_u]Perry[/name_u])
As for middles:
I’d choose
[name_m]Solomon[/name_m] Twilight ([name_m]Sol[/name_m], [name_m]Solly[/name_m] or [name_u]Sal[/name_u])
[name_m]Robert[/name_m] [name_f]Starling[/name_f] ([name_m]Rab[/name_m] or [name_u]Bobby[/name_u])
[name_u]Laurence[/name_u] [name_m]Toulouse[/name_m] ([name_u]Ren[/name_u] or [name_u]Laurie[/name_u])
[name_m]Louis[/name_m] [name_m]Columbus[/name_m] ([name_u]Lou[/name_u])
[name_m]Ivan[/name_m] [name_f]Orchid[/name_f]
[name_m]Joseph[/name_m] [name_f]Cricket[/name_f]
[name_m]Allen[/name_m] [name_f]Heather[/name_f]
[name_m]Nicholas[/name_m] Foxglove
[name_m]Thomas[/name_m] [name_u]Mercury[/name_u]
[name_m]Lewis[/name_m] Otter