I think your DS is getting lots of variety. If he eats a proper dinner then all of the things you have said he likes actually make up alot of lunch options.

One thing that my DS likes (and we all eat) is what we call 'DS's Special Soup'. We make it with minced turkey, but have used minced chicken and pork too, we add ginger, lemongrass, grated carrot and small pieces of broccoli. Sometimes we add black quinoa but always we add little pasta shells. DP and I eat it as a soup but mainly we drain the broth off for DS and give him the meat, pasta and veggies. He loves it. I put leftovers into small containers and freeze so he can have it again for lunches.