2% or whole milk would work just fine.
yes you can'pretty much milk is milk no matter what it is labelled
Yes you can, the fat content in milk .04 - 3.5% has little effect on a recipe. One cup of whole milk contains 9 grams or a little less than 2 tsp of fat. 2% milk has about 1 tsp of fat.
Yes, you can use buttermilk with baking powder.
You can substitute powdered unflavored coffee creamer for powdered milk.
Yes or water if you add a little extra fat.
You can, but it will require cooking to thicken and reduce the recipe. It is easier to use powdered milk, although the authentic recipe uses carabao's(water buffalo) milk AND requires cooking to reduce and thicken the pastillas.
Yes: you can use a greater volume of fresh milk (preferably scald it first) instead of powdered (substitution charts range from four to 9.5 times the amount of fresh milk instead of milk powder). In many recipes you can just leave out the milk. Or use dried buttermilk, or malted milk powder.
It will not be quite as rich but it should set up and be fine.
Yes, just be careful with the baking temperatures and how dense you want the bread to be. Many white breads actually ask for warm milk instead of water.
When cooking with normal milk it will curdle. Always use evaporated milk in recipe when possible. Evaorated milk can be used instead of cream as it is lower in fat. however if substituting evaporated milk with regular milk, remember that evap milk is called evap milk for a reason. for 1 Cup of regular milk, you must only use 1/2 Cup of evap milk and 1/2 Cup of water. mix the 2 together and it should work in the recipe. i have never had a problem with this.
Since powdered eggs are going to be scrambled or used in a recipe, it shouldn't be a problem.
use powered milk aka non fat dry milk