Can regular whole wheat flour be used, instead of pastry flour? Also, is "fine grind corn meal" something like "Maza Harina"?

Whole wheat pastry flour is made from the soft wheat berry. It is lower in protein and gluten than whole wheat flour and doesn't have the "tannic" flavor of whole wheat flour. The best substitute for it would be all purpose flour.
The alkaline treatment of corn that allows for it's easy removal from the hull has 3 positive side effects. It allows niacin to be absorbed from the corn, it keeps the corn from sprouting and it chemically changes it so when ground fine it can be made into a dough to make tortillas.

If you use whole wheat non-pastry flour, you would want to handle the flour gently, as you would do for muffins, to prevent a tough, dense bread. Also, many brown bread recipes use all-purpose white flour. The 'brown' is usually from molasses.

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Masa harina is dried and powdered dough made from ground hominy, so while it is a corn meal of sorts it isn't the same as fine cornmeal. (Hominy is corn that has been treated to soften it and remove the hull.) As far as replacing the pastry flour with regular whole wheat, you could, but pastry flour is lower in protein than regular flour, and is typically used to tenderize, so you'd end up with a tougher, probably denser loaf.