Congratulations!
My thoughts on your list
[name_m]Frederick[/name_m] ~ I think [name_m]Frederick[/name_m] is really handsome very distinguished, wholesome and cosy. However I agree T3ddy & [name_m]Freddie[/name_m] is a bit too matchy.
Julian/Julius ~ I think more names are really lovely. [name_m]Julian[/name_m] is very soft, relaxed, smart and handsome. [name_m]Julius[/name_m] I suppose feels more interesting, more distinctive and sophisticated. I like both however I think [name_m]Julian[/name_m] feels more fitting with your sibling set.
[name_m]Alexander[/name_m] ~ I like [name_m]Alexander[/name_m] the name is smart, distinguished and rich in history. I also like the nickname [name_m]Xander[/name_m]. Personally I think [name_m]Alexander[/name_m] feels ‘common’ however the reality is I rarely encounter young children named [name_m]Alexander[/name_m]. I think he’s handsome and sounds strong in your sibling set.
[name_m]Benedict[/name_m] ~ I really like [name_m]Benedict[/name_m] I think he’s so sophisticated, gentlemanly, with a lovely meaning ‘blessed’ and he’s very handsome. I love the nickname [name_m]Ben[/name_m] it’s just sweet and reliable. I think [name_m]Benedict[/name_m] is very cohesive within your sibling set.
August/Augustine ~ Personally I do like August/Augustine but I wouldn’t reuse this name when A.ugustus already features within your sibling set.
[name_m]Constantine[/name_m] ~ I think [name_m]Constantine[/name_m] is very lovely however the name feels bold in comparison to the other names in your sibling set.
You’ve had lots of lovely suggestions so count any repeats as me being in agreement with the berries
[name_m]Nathanael[/name_m] ‘Nate’
[name_m]Sebastian[/name_m] ‘Seb’
[name_m]Christopher[/name_m] ‘Kit’
[name_m]Oliver[/name_m] ‘Ollie’
[name_m]Abraham[/name_m] ‘Bram’
[name_m]Samson[/name_m] ‘Sonny’
[name_m]Gabriel[/name_m] ‘Gabe’
[name_m]Willoughby[/name_m] ‘Will’
[name_m]Callum[/name_m] ‘Cal’
[name_m]Zachariah[/name_m] ‘Zach’
[name_m]Rafferty[/name_m] ‘Raffy’
[name_m]Jeremiah[/name_m] ‘Jem’
[name_m]Rupert[/name_m] ‘Rue’
[name_m]Patrick[/name_m] ‘Patch’ or ‘Paddy’
[name_m]Reuben[/name_m] ‘Rue’
[name_m]Solomon[/name_m] ‘Sol’
[name_m]Sullivan[/name_m] ‘Sully’
[name_f]Hope[/name_f] this helps