YEs you can
Yes, you can.
No, because the shortbread will rise. You can use plain flour or rice flour instead though. it would be really nice.
You can use plain flour with a teaspoon of baking powder.
Corn flour is quite different to regular flour and most recipies will fail if you use the wrong type of flour.
Yes you can, I use whatever flour I have to hand.
I sometimes use pancake mix
When you are baking cakes and pastries which are cream based then its must to use refined flour
For thickening soups, stews, and gravies, you can use flour instead of cornstarch.
yes
When making Sorghum
Use wholemeal flour instead of white - OR - replace some of the white flour with bran.