Fire up a comal on the stovetop. Rinse the poblano chiles and bell pepper thoroughly and pierce each with a knife. Place them on the comal and let them roast evenly. You will have to keep an eye on them, making sure to turn them over until all sides are roasted. When done, the skins should be evenly blistered and mostly black.
Place roasted chiles and pepper into a plastic bag and close the bag. Cover the plastic bag with a kitchen towel. The steam will help the blackened skin to separate. When cool, rub off the blackened skin, careful to keep the stem intact on the poblano chiles.
Using a small sharp knife, carefully slit chiles open along 1 side. Remove seeds, leaving stems attached. Set aside to fill later.
Chop the bell pepper and discard stem and seeds.
Preparing the filling:
Heat a large skillet over medium-high heat. Add oil to pan; swirl to coat. Sprinkle shrimp with 1/4 teaspoon salt. Add shrimp to pan; cook 3 minutes or until done. Remove from pan.
Add garlic to pan; sauté 30 seconds, stirring constantly. Sprinkle with flour and ground red pepper; cook 1 minute. Slowly add crema Mexicana, stirring with a whisk. Stir in 1/2 cup milk; cook 1 minute, stirring constantly. Remove from heat; let stand 2 minutes. Add quesadilla cheese and 1/4 teaspoon salt, stirring until smooth.
Place 1/3 cup cheese mixture in a large bowl; reserve remaining cheese mixture. Add bell pepper, shrimp, cilantro, and juice to 1/3 cup cheese mixture in bowl; toss to coat. Stir 1/4 cup fat-free milk into reserved cheese mixture.
Spoon 3 tablespoons of cheese sauce on 4 plates.
Stuff each poblano chile with 6 tablespoons shrimp mixture.
Place 2 stuffed poblanos on cheese mixture and garnish with crumbled queso fresco, cilantro, and pomegranate seeds (optional).
You can use light cheese to lower the calories even more.