Liking the suggestions of [name_u]Robin[/name_u] and [name_m]Bram[/name_m] (though [name_m]Abram[/name_m] would fit the sibset slightly better imo).
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Harvey[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Bernard[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_u]Tristan[/name_u]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Wilfred[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_u]Morgan[/name_u]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Alistair[/name_m] / [name_m]Alasdair[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_u]Florian[/name_u]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_u]Sidney[/name_u]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Oscar[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Quentin[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Harold[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Torquil[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Declan[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Marshall[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Lorcan[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Roald[/name_m] / [name_m]Ronald[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Edmund[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Hector[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Conrad[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Otto[/name_m]
[name_m]Peter[/name_m], [name_f]Eugenie[/name_f], & [name_m]Rupert[/name_m]