Mary Vangoven Velden Brewer (Brewer?) - Help?

I see a marriage record for a Mary widow 1) Vangoven 2) Velden who married a John Brewer
She is attached to parents and the only Thomas Velden I can find is a Thomas Van Der Velden at FamilySearch

Daughter Mary Anne "Polly" Parker who is seen as wife of Stephen Parker is seen at Ancestry as a daughter of William or Harry Brewer or no parents listed at all and the marriage record for her and Stephen says 1797 which is long after his death date as noted on all these trees.
I have messaged managers.
I wonder if some of the profiles have been conflated?
Thank you for any assistance