I always headcanoned the refugee issue as a whole lot of Bajorans getting off-planet early in the war (and in lesser numbers throughout the occupation, plus escaped slave laborers and Maquis members who eventually had families and needed to move them out of Maquis areas) and that was where Ro's family went; Kira's family stayed on Bajor. It would have been very interesting to have more refugee Bajorans coming back, whether or not it could have been Ro herself!