Is there a term for children whose parents' marriage ends with nullity? In its discussion of marriage, the Catechism of the Catholic Church (CCC) states, "The Church holds the exchange of consent between the spouses to be the indispensable element"(CCC 1626) that seals the covenant of matrimony. "If this freedom is lacking, the marriage is invalid." (CCC 1628)

The CCC goes on to say, "For this reason (or for other reasons that render the marriage null and void), the Church ... can declare a nullity of marriage, i.e., that the marriage never existed." (CCC 1629)

In consideration of this, it lends to question what the nature of the sexual relations were if the marriage never existed. However, that's an aside; it's the children of such a union I'm asking about. Presumptively, these are children baptized in the Church with godparents.

Is there a term for children born from what was thought to be a valid Catholic marriage whose parents then go through legal divorce and the Church delclares the marriage null? Please no derogatory answers, but if there's something "you've heard somewhere," feel free to add as a comment with some context.
Yes, there is a term: legitimate children

Canon 1137 of The Code of Canon Law:


  “The children conceived or born of a valid or putative marriage are
  legitimate.”


Canon 1061 of the Code of Canon Law 


  “An invalid marriage is called putative if it has been celebrated in
  good faith by at least one of the parties, until both parties become
  certain of its nullity”. 


There is no stain, and no fault, laid upon any child under canon law due to a decree of nullity.  

Beyond that simple term, based on your presumption


  Presumptively, these are children baptized in the Church with godparents.  


there is another term for those children:  Baptized Catholics.