Mary Jenckes - yes, the keying instructions for spouse's father's surname state "If no surname is stated, the spouse father's surname should be keyed from the child's surname."
David -this is more puzzling. I think it is a typesetting error, and is supposed to be two different marriages - David Condron married Deborah, and then Maria F Remington married someone else but they have missed his name out. FamilySearch have Maria F Remington marrying Thomas H Condy on that date at Providence, but of course we aren't allowed to copy information from that site and have to work with what it says on the image! I suspect that Deborah's surname was not Brovidence but something else beginning with B, and then the rest of her name and a line or two got lost and her name got stuck onto the end of the place name "Providence".
Anyway... as I said, we are supposed to key what is on the image, not to correct errors, so I think what you have to do is to key it as two marriages:
David Condron married Deborah Brovidence 23 Aug 1815
David Condron married Maria F Remington 23 Aug 1815.
I don't think there are many errors like this in the project, thank goodness!