Not overeating is the best approach. But there is no reason to eat small meals that leave you hungry. Coffee doesn’t bother most people if they are eating low FP. I know of one person that believes coffee, even without sugar or high lactose milk contributes to his reflux. There is an unproven idea that caffeine relaxes the LES. Also, recently, I came across some info suggesting that coffee may actually contain some fermentable carbs 2-4 grams, but can’t put my finger on the source at the moment. In general, a couple of cups of coffee per day should not be a problem.
As far as combining approaches, trying one approach at a time makes better sense to me. It’s easier to determine if the approach works.