DH loves these. I’ve nixed them in the past due to popularity but the funny thing is, I never see or here of new [name]Natalie[/name]'s. Is it really that overused? I know it’s making a comeback.
[name]Do[/name] you prefer [name]Natalie[/name] or [name]Natalia[/name]? Does [name]Natalia[/name] feel overly ethnic to you (sometimes I think it’s to Russian for our family?). Does either one go with [name]Owen[/name]/[name]Sullivan[/name]/[name]Annabel[/name]?
I prefer [name]Natalie[/name], because I think it has a softer, sweeter sound than [name]Natalia[/name]. I think [name]Natalie[/name] also goes with [name]Owen[/name], [name]Sullivan[/name] and [name]Annabel[/name] better than [name]Natalia[/name].
I dont see [name]Natalia[/name] as linked too much to any specific culture, while it surely feels more “ethnic” than [name]Natalie[/name], I know a Spanish [name]Natalia[/name], a Polish [name]Natalia[/name], and an Italian [name]Natalia[/name]. 
While I prefer [name]Natalia[/name], I think [name]Natalie[/name] is a better match for siblings. It’s very pretty and I have only ever met one [name]Natalie[/name] (she’s in her early 20s now).
I think [name]Natalia[/name] is ethnic, which would be fine if it fits with your culture. I am plain caucasian and would use [name]Natalie[/name].
I think [name]Natalie[/name] is better match for the sibling set. Also, I don’t know of any new [name]Natalie[/name]'s or of any [name]Natalie[/name]'s under the age of 25 even, so I tend to not think of it as overused.
I just made a topic asking this!
There were a lot of replies, so perhaps you’ll find some that help you with your decision 
I like [name]Natalia[/name] more than [name]Natalie[/name] at times, usually because [name]Natalie[/name] is kinda cutesy to me. I think it’s the ee sound at the end. Whereas [name]Natalia[/name] is more mature sounding. I like the nn [name]Talia[/name] more than [name]Tallie[/name] as well.
[name]Natalia[/name] is more exotic to me, rather than ethnic. [name]Natalya[/name] would be more ethnic to me, than exotic.
I know two Polish origin Natalias, they’re 5 and 6.
I do think that [name]Natalie[/name] fits your sibset much much better than [name]Natalia[/name].
I prefer [name]Natalia[/name] over [name]Natalie[/name]. It’s very pretty, and not so much ethnic as exotic and striking. I like the nickname options of [name]Tallie[/name] and [name]Talia[/name].
That being said, I prefer [name]Natalie[/name] for your sibset. I think it goes much better than [name]Natalia[/name]. While the two names are similar, their styles are really different.
I agree.
I’m biased, my sister is [name]Natalie[/name], so I love it because of her. We haven’t really met that many other Natalies, maybe six, tops? And that’s since my sister was born 16 years ago, and I’ve been keeping tabs. I think it’s a great name, and the nn [name]Tallie[/name]/[name]Allie[/name] is super cute.
In your case I think I prefer [name]Natalie[/name]. I only know two Natalies…one is 28, one is closing in on her first birthday.
I like [name]Natalie[/name]. I only know one [name]Natalie[/name] so I don’t think it’s too popular.
I prefer [name]Natalie[/name] in general and also with your other kids names. my niece (16) is [name]Natalie[/name] and I also know a 5 year old and 4 year old (around my daughter’s age), but that’s it. I think it is one of those names that is a “current classic” i.e. it is around but not overly popular and I think will retain its appeal and i don’t get the sense it will become dated but would rather be a long time choice