With Caleb, my 10 month old, I would add some formula into the applesauce that we used for his enzymes. That way I knew he would get those extra calories in no matter if he breastfed alot or not. I am not sure if rice cereal has more calories, but if it does, you could try ading that to the applesauce instead.
Flax seed oil might be a good thing to put into his bottle. Caleb now gets it in his mushed veggies and he does great with it. It is great for those young brains and adds some good fat to the tummy.
Your baby is so lucky to have you. Most CF teams knows a lot but not everything. My husband and I usually listen to the team and then come up with a plan of lets try some of our own ideas, or those on this forum and then go with what works the best for our kids.
Blessings,
Missa