All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
You should know, dear brother, that a daughter of paternal uncle is not among the heirs and so, she does not inherit the daughter of her paternal uncle. Also, it is with greater reason that her children do not inherit the daughter of the paternal uncle of their mother.
However, the son of paternal uncle is among the heirs but he does not inherit except when there are no male relatives who are closer to the dead than him.
The details which you mentioned in the question are not enough to clarify how the inheritance should be divided because all the heirs should be defined and known.
Therefore, we advise you to take the case to an Islamic court if any, or to orally expose the case to the scholars so that all the heirs could be known.
Allaah Knows best.