Couldn't find gluten free lasagna so we just swapped this into a pasta casserole. We used frozen broccoli, cauliflower, and peas for our veg. One whole box of barrillos gluten free ziti pasta instead of lasagna. My wife hates cottage cheese and ricotta, so I used baby swiss instead. Worked out pretty well!
We needed like a LOT more than 2 cups of vegetables to layer up. This recipe also didn't list a pan size, so maybe that was a factor. Everything else worked out fine.