Name for brother of Cornelius

I am trying to find the right name for our new baby boy. We need an international name that is easy to pronounce (he is half Danish, half English), fits well with the chosen middle name [name]Charles[/name], and has a similar style to his brother [name]Cornelius[/name] [name]Karl[/name].

An name which works in Danish and English and sounds good with [name]Cornelius[/name], let me see …
[name]Caspian[/name] (if you don’t mind two C names)
[name]Cyprian[/name] (not sure if this works in Danish)
[name]Phineas[/name] “Phin/[name]Finn[/name]”
[name]Tarquin[/name] (again, not sure if this works in Danish)
[name]Thorian[/name] (or Thorben/[name]Thorsten[/name])

[name]Do[/name] you call [name]Cornelius[/name] by a nickname? If you do, I think it would be possible to use another -us name. There are some great ones that I think would work, including :

Good luck! [name]Auburn[/name]

[name]Cornelius[/name] [name]Karl[/name] and [name]Odin[/name] [name]Charles[/name]
[name]Cornelius[/name] [name]Karl[/name] and [name]Soren[/name] [name]Charles[/name]
[name]Cornelius[/name] [name]Karl[/name] and [name]Bram[/name] [name]Charles[/name]