Question regarding status of a previous marriage
A woman was previously married in a conservative wedding and divorced shortly thereafter.
The woman then remarried to another man again conservative. She had 3 children from this marriage and has since also divorced, 2 of these children have grown up to marry and have children of their own.
it was discovered in pictures from the wedding that the eidim for the ketubah and chuppah were male and female.
What is the status of the woman, her children and grandchildren?
The validity of a conservative wedding depends very much on the specific details of the one who officiated and how he did so. There are times when a basically halachic ceremony is performed. The male and female eidim would not be valid, but Igros Moshe does raise the possibility of there being other kosher witnesses in attendance which could give validity to the marriage.
Generally she should try to obtain a proper get from such a marriage, unless it can be clarified without a doubt that there was no halachic validity. There is usually room for leniency to avoid mamzer status for the children, but this should be checked out by someone familiar with details of the case.