[name_m]You[/name_m] have a great list! All the names would suit your family but the stand out for me is [name_m]Bruno[/name_m] – different ending sound, and feels quite friendly and easy going like your older sons’ names. My next favourite is [name_m]Frederik[/name_m] which has a more distinguished feel. Both options make the intentional connection.
[name_m]August[/name_m], [name_m]Leon[/name_m], [name_m]Sebastian[/name_m] and [name_m]Hugo[/name_m] are all mainstream choices here in [name_m]Australia[/name_m] so they don’t necessarily read as international if that’s important to you.
A few ideas:
[name_m]Marcel[/name_m]
[name_m]Nico[/name_m]
[name_m]Marius[/name_m]
[name_m]Lars[/name_m]
[name_m]Anselm[/name_m]
[name_m]Blaise[/name_m]
[name_m]Artem[/name_m]
[name_m]Franz[/name_m]
[name_m]Kosmo[/name_m]
[name_m]Lev[/name_m]
[name_m]Fabian[/name_m]