While your specific Rykman line is not familiar to me, you can tell a great deal from the naming pattern used by the parents.
Johannes Polhemus' parents were Theodorus P. and Margrietie Remsen (according to published genealogies). Now notice the name of John P and Maria Rykman's second son (Theodorus) and first dau. (Margaret which is Margrietie/Grietie) You have a very traditional Dutch naming pattern here! First born dau after father's mother, therefore second born dau should be mother's mother (it is Cornelia). Second born son after father's father therefore first born son (Tobias) should be after mother's father
Tobias IS a Rykman name -- and I had a look at various church records for a Tobias and Cornelia with the result that I found Tobias and Cornelia Rykman being bpt sponsors in Tappan RDC in 1765.
Further checking showed that on 9 Nov 1749 in New York City RDC, Tobias Rykman married Cornelia Kip.
I suggest these are the parents of your Maria Rykman. I'd check Tappan RDC bpt, New York City bpt and any other nearby church for the bpt of Maria/Marritie --- but I think you have a good case for Tobias R and Cornelia Kip.
Did any Kips stand as bpt sponsors for the children bpt to Johannes P and Maria R? That would be more evidence of the parents I'm suggesting.
You can also check the Dutch Colonies mailing list archives to read about your surnames.