Did they replace Kiera’s voice with Natalie’s? That is a good question. I’ll see if I can find any info on that.
And you’re right, it is even higher-pitched in the trailer. But see, I like that. It definitely makes Anakin and Padmé feel closer in age, and I think it makes her at least somewhat more sympathetic. I definitely would want to reimplement her actual voice pitch for any future fan edit I might do.
Honestly, I feel if you were to improve Padmé’s character arcs in 2 and 3, she would be a clear main character of the films, at least alongside Anakin. Maybe they both would be comparable to how Rey and Kylo Ren are dual main characters of the ST.