Maybe [name_m]Henry[/name_m] or [name_m]Jude[/name_m]? I also like these:
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Leo[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Bennett[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Ellis[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Miles[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Arlo[/name_m] (Margot and [name_m]Arlo[/name_m] is probably too similar in sound, though)
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Finn[/name_m] or [name_m]Flynn[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Isaac[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Levi[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Nico[/name_m]
[name_f]Margot[/name_f], [name_m]Graham[/name_m], and [name_m]Peter[/name_m]