I'd also say it looks good. You're already feeding him a bunch of the stuff I was going to suggest. I would take the day care SERIOUSLY to task for the, um, cr@p they're feeding your DS too.
We have issues here with high fructose corn syrup, so I TOTALLY hear you on the sugar concerns.
The only other stuff I can recommend would be fish oil (Nordic Naturals makes lemon- and orange- and peach-flavored fish oil which DOES NOT taste fishy!!!); we often mix it with full-fat yogurt and a bit of vanilla and the orange makes it taste like creamsicles when we sweeten it a bit with a drop or two of stevia.
Oh, and you say he's not into avocado any more, but will he eat guacamole, with all the seasonings? Makes a great dip for cheese, crackers, cukes, carrots, the works, and you can add olive oil. We've also successfully sneaked pureed broccoli and kale and spinach into guac on one occasion or another. How about ranch dressing, made with the yogurt?
If you're leery about any more dairy, you can add protein powder to milk or even rice milk; Natalie CHUGS rice milk with rice protein powder we get at Whole Foods; it also happens to be loaded with green veggies like kale and spirulina and dandelion and beet greens, but she doesn't need to know that.
Will he eat fish at all? My girls will both eat salmon that's been marinated in and then baked with a can of coconut milk, and coconut is LOADED with good fats.
(The coconut is good in veggie curry too!
Coconut oil in general has lots of health benefits and we cook in it pretty often, even to make popcorn (which I make in my pasta pot with the colander-type lid).
Eggs? Even with his own selection of seasonings? Both my girls enjoy exploring the spice cabinet and smelling/tasting the contents thereof, and we have a pretty amazing one as we like ethnic touches in our food. (In our house, for example, many meat dishes aren't complete without the tiniest sprinkle of cinnamon.
Anything in there to work with?