If you warm his bottle, just make sure to add the probiotics AFTER warming it. The warming process (microwave, etc.) could make them less potent, but adding them after the formula is already warmed should be fine (that’s what I do).
Trienza is a great comprehensive digestive enzyme. Paige is about 27 pounds, and our doctor recommended we give her about 1/2 capsule with each meal. I usually open up the capsule and mix half of the contents into a small bowl of fruit sauce and feed her that at the beginning of the meal. I’m sure any soft/pureed type food would work. It doesn’t really mix well into liquid, so I find the pureed food to be easiest.