Do the son of the sister, the son of the daughter of the sister, and the daughter of the daughter of the sister inherit from a woman who died and has no heirs other than them, and what is the share of each of them, or does her estate go to the public treasury?

If a woman leaves no inheritor by fard (prescribed share) or ta'sib (agnatic relation), her estate transfers to her dhawu al-arham (uterine relatives), who take precedence over the public treasury (bait al-mal). The relatives mentioned are among the dhawu al-arham. However, it is not possible to determine the method of distribution due to differences in the madhhabs (schools of thought) regarding tanzeel (assigning heirs the share of their ascendants) and qarabah (proximity of kinship) in inheriting from dhawu al-arham, and due to insufficient information about the kinship between the mentioned sisters. It is advisable to consult with scholars of knowledge in your country.