Hi. I am new here to "The Trek BBS". I cam across this story when looking up info the Avantine. I have to say that I like a story that delves into Ezri this way as I have found it, at least in the fanfic community, hard to find stories centered on her. Something that struck me when reading the latest post was that, thought Dax has had some notoriety in past lives, this is the first time Ezri has had to deal with fame as Ezri in contrast to as part of Dax's legacy. As for Spock I think you have him down perfectly.
I look forward to seeing how to two of them interact in coming chapters. The two of them did after all live through the same time frame and probably have a lot on topic they could talk about. I also have this nagging thought of a scene beginning with Ezri saying "... and then Captain Sisko had the Tribble with the bomb beamed into space."
Overall I hope you might do a few other Ezri or Aventine short fic as after reading this it looks like it could fun to read.