I was told to avoid pasta, bread, and tortillas for at least the first year because they can form a lump of food in the stomach that is painful to digest. I don't know if that's true or just a scare tactic to keep us away from "bad" foods, but I think someone like you who is already having problems with liquids and purees should definitely be cautious and avoid these foods.
How about eating the lasagna without the noodles? You can probably pull the noodles out. Ricotta bake is basically lasagna filling, so you can try that. I added some turkey meat sauce to it once I started eating meat, which makes it meat lasagna sans noodles (but I would suggest starting without meat). If your goal is just to get carbs, maybe try diluted apple juice; this is what I was told to do in the liquid stage. Ensure High Protein shakes also have relatively high carbs, and that's what they gave me in the hospital. You could also try unsweetened applesauce.