I don’t think [name_f]Anna[/name_f] in itself is plain, but I understand your concern when considering your sons names. From your list I like [name_f]Karolina[/name_f] the most and think this would match very well with [name_m]Christian[/name_m] and [name_m]Dominic[/name_m].
[name_f]Natalia[/name_f] - I really prefer [name_f]Natalie[/name_f] myself. Also meaning wise you would have two children relating to christmas, [name_f]Natalia[/name_f] and [name_m]Christian[/name_m] something to consider or love…
[name_f]Tatiana[/name_f] - princess from the disney movie
[name_f]Karolina[/name_f] - sounds a bit more sophisticated which I like
If the [name_f]Ania[/name_f] nickname is important to you maybe look for other names that can be shortened to [name_f]Ania[/name_f] such as:
Aniela
[name_f]Anastasia[/name_f]
There are lots of different countries and languages in Eastern Europe. But I’m guessing from your list that you’re looking for Polish or maybe Russian names?
I think any of those names would go well with [name_m]Christian[/name_m] and [name_m]Dominic[/name_m]. I like [name_f]Anna[/name_f] very much and I don’t find it to be too plain. [name_f]Ania[/name_f] is a very sweet nickname.
I also like:
[name_f]Feodora[/name_f]
[name_f]Gala[/name_f]
[name_f]Inga[/name_f]
[name_f]Irina[/name_f]
[name_f]Ksenia[/name_f] (one of my all time favorites)
[name_f]Violetta[/name_f]
[name_f]Yelena[/name_f]
I tend to prefer the [name_f]Anja[/name_f] or [name_f]Anya[/name_f] spellings to the [name_f]Ania[/name_f] spelling but think either way it’s a sweet name (no longer version needed).
[name_f]Anna[/name_f] is fine, but maybe [name_f]Anya[/name_f] or [name_f]Anja[/name_f] to give it some pizazz? I love [name_f]Anastasia[/name_f] and [name_f]Ana[/name_f] is a great nn for this. [name_m]Christian[/name_m], [name_m]Dominic[/name_m], and [name_f]Anastasia[/name_f] are a lovely sibset. One of other my favorites is [name_f]Edita[/name_f] (eDD-EEta).
Some more possibilities:
[name_m]Christian[/name_m], [name_m]Dominic[/name_m], and