congratulations! sending you the best wishes on your pregnancy 
from your list, i especially love [name_m]Rory[/name_m] [name_m]Malcolm[/name_m] and [name_m]Jonah[/name_m] [name_m]Malcolm[/name_m]
[name_f][/name_f]I love that [name_m]Rory[/name_m] and [name_m]Jonah[/name_m] both have some similar elements (shared sounds, same syllables) with [name_f]Clara[/name_f], without sounding to match-y.
[name_f][/name_f]I personally don’t love matching sibling initials, so ruled out [name_m]Charlie[/name_m], [name_m]Callum[/name_m], and [name_m]Calvin[/name_m], and I just don’t think [name_m]James[/name_m] and [name_m]Leo[/name_m] stand out next to [name_f]Clara[/name_f]!
[name_f][/name_f]Some other suggestions for you:
[name_f][/name_f][name_m]Oliver[/name_m]
[name_f][/name_f][name_m]Thomas[/name_m]
[name_f][/name_f][name_m]Remy[/name_m]
[name_f][/name_f][name_m]Henry[/name_m]
[name_f][/name_f][name_m]Milo[/name_m]