There is one caution I would give from personal experience. It can be a pain for the kids if their names rhyme too closely. My brother and I (Justin and Kristen) could never quite tell which one of us my mother was calling, which meant she had to call twice. Which meant big trouble.
Out of the ones you listed the ones I think would work the best are Serena or Ariela. Aria is OK but nms. I don't like Suri (I've only ever met men with this name) and somehow I just think Talia is a little too close to Ayla in sound. Other ideas: Lena, Esme, Miranda, Lucia...
Re: Good sibling name?
Ayla and Sari would be cute!