These are my current favourite names:
[name_f]Keziah[/name_f] and [name_m]Artemio[/name_m].
They both seem prone to nicknames, so I wonder what they might be. What do you think?
Also, I’m not 100% sold on these two as a sibset. Other sibsets I like are;
[name_f]Hazel[/name_f] and [name_m]Ikaia[/name_m]
Ronina and [name_m]Viggo[/name_m]
[name_f]Magda[/name_f] and [name_m]Eben[/name_m]
Which one do you prefer?
These are the first nn’s that come to mind…
Keziah nn’s: Kez, Kezi, Kia
Artemio nn’s: Art, Artie, Temy, Mio
From your other sibsets I really like Eben & Magda! My runner up would be Ronina & Viggo. Hazel feels a bit out of place next to Ikaia in my honest opinion.
If I were to mix & match them I think Viggo & Magda would be really sweet together as well!
I’ve never seen [name_m]Artemio[/name_m] before but I love it! [name_f]Keziah[/name_f] and [name_m]Artemio[/name_m] sounds like a fantastic sibling set.
I second @rhodes2nowhere’s nickname suggestions
For [name_f]Keziah[/name_f] I might add [name_u]Zia[/name_u]
Adding [name_u]Ari[/name_u] for [name_m]Artemio[/name_m]! 
[name_f]Keziah[/name_f] and [name_m]Artemio[/name_m] are cool!
Me and my husband decided to name our son [name_m]Artemio[/name_m], he was born this year. We like the nickname [name_m]Arte[/name_m] or Mio… I’m also Polish so it fits the cute nickname Artuś (from Arthur)