The finding aids and indexes (not online) of the Alberta Genealogical society list 6 Nunnemaker names among them is;
Robert Nelson NUNNEMAKER, 1858 - 1941 buried in the Brooks Cemetery.
The others are all in the Suffield area, and no Mary.
I would suggest that you contact the AGS Brooks Branch as they would have more local search material.
Also the AGS Research Group at the Edmonton Branch has access to reseach material at the Alberta Provincial Archives.