This is a sensitive question I am asking for a person who wishes to remain anonymous.
It is regards a Kohen married more than one time. The children of one of the marriages are from a marriage from Kohen and a divorced woman. Are the children then Chalalim? Are they permitted to marry and who can they marry? Also, are they Jewish if the mother is Jewish?
If the mother is Jewish the children are certainly Jewish, but if she was divorced they will, as you note, be chalalim.
This means that they have the general halachos of a Yisrael, rather than a Kohen.
For male children, there are no restrictions on marriage. For female children, the daughter (a chalalah) can marry anyone except for a Kohen.
The status of a chalal continues to the next generation from father to son.