Can you use regular rice in a recipe that calls for instant rice?

It may depend on the recipe. But often they are interchangeable. Quick oats absorb moisture faster than regular rolled oats thus they cook faster. Most baking recipes and granola recipes don't need a high absorption rate because they are cooked for 20 minutes or more. If the recipe does not cook the oats for at least 15 minutes then presoak rolled oats ( in liquids needed in the recipe) for 10 minutes before using or use the quick oats as called for. (granola recipes often do not require the oats to absorb the liquids, so either type should work).