Do the children of the sister have a right to inherit from their maternal aunt, who died in 2012, after their mother (the sister) died in 2011, and the deceased aunt has an inheritance from her father and did not bear children?

The children of the deceased's sister, both male and female, do not inherit from their aunt. They are not among the inheritors but are considered 'dhawu al-arham' (relatives by blood, but not entitled to a share of inheritance). However, they would inherit if the deceased left no 'asabah' (agnate heirs) or 'ashab al-furud' (Quranic heirs) from their relatives.