No, you're not wasting your time. We need trainees, even for life. You may even need 2 years of CCM, just to be able to take care of your peds patients. I only had one month of PICU during my year of fellowship, definitely could have used two.
You're basically getting into peds plus geriatrics. Your breadth of passion and future competence is beyond admirable. I am sure every employer will be just speechless. You'll be more respected than the IM-Peds people. The academic hospitals will gladly pay you extra for being the pediatrician in the adult ICU and the adult intensivist in the pediatric ORs; imagine how much you could teach in both places about the other.
We need more real doctors like you, especially in rural Alaska. You will give a new meaning to "well-rounded physician", more than just being obese.