R.,
You may have to become the sneaky chef. Also, it sounds like you are using packaged and processed foods (no judgement!), but you may need to make the packaged foods homemade.
my daughter is almost 2 and the pickyness is so challenging. One day she eats something, next day---no way tis life! Anyway, my little one is primarily vegetarian. I always make sure that at every meal she gets whole grain, protein and a fruit or veg. In your case, I would convert all of his favorite foods into a whole grain or veggie option: brown rice, whole grain bread for homemade french toast, whole grain pasta and veggie dogs (I think smart dogs taste EXACTLY like regular, and he's not getting the nitrates or the pig eyelid that he gets in a regular hot dog). Also use sweet potato fries instead of regular---lots of vitamin A and they are yummy!!! Quorn makes great meatless nuggets (soy free)--they taste just like chicken!! Spelt crust pizza (he can help you make it homemade)
Next, I would make a puree: fresh carrots, corn, spinach, broccoli, tofu. Steam/sautee, TASTE to ensure it's yummy and puree. You can freeze it.
I use these nutritious purees for EVERYTHING I can!!! Recently I used Bob's red mill 10 grain pancakes (yummy), mixed it up and added 1 cup of veggie puree. She LOVED them (you can also add 1/2 cup of cheese, but I stay away from dairy, esp when its cold). They are super nutritious, and you can freeze left overs and heat one up. Sometimes she just wants 1-2 pancakes, a bowl of brown rice, and some scrambled egg for dinner.
Also, pick up some flax seed meal. You can add it to organic yogurt, cookies (also use oatmeal, raisins, carob chips) , brown rice pudding, homemade banana bread, etc.
finally, remove the white sugar, and use succanat for all of the things you make that require sweetening. Also, ONLY use Grade A real maple syrup. The commercial syrups are cheaper, but made with a LOT of awful stuff like high fructose corn syrup (there is MERCURY in that stuff)
My motto is healthy, yummy, homemade and quick!
Overall, you need to be sure every meal is made in the healthiest way possible, and in case he does not want to eat, at least you tried.
Feel free to email me if you need other ideas. Good luck