Preheat oven to 350 degrees. Grease an 11"x7" baking dish and set aside.
In a small saucepan, cook rice in 1 1/2 cups of water until boiling. Stir, cover and turn heat to low. Steam for 15 minutes.
In a large skillet on medium high heat, melt butter. Add onion, celery and carrot and cook until tender. Add garlic, salt an pepper and cook for 1 minute longer.
Add cooked rice, dill and parsley to skillet. Stir to combine. Transfer rice to prepared baking dish and press down to evenly distribute.
To a medium saucepan, add water to fill halfway. Bring water to a boil and add shrimp and scallops. Reduce heat to medium and cook for 5 minutes or until scallops are firm and shrimp are pink.
Drain water from seafood, reserving 1/2 cup. Transfer shrimp and scallop to a large bowl. Add crab and gently combine. Set aside
In a small saucepan, melt butter over medium. Whisk in flour until golden. Stir in the milk and reserved seafood water.
Turn heat to low and add cream cheese, salt, pepper, dill and thyme. Stir until cheese is melted and combined.
Pour cheese mixture over seafood and combine, Pour this mixture over rice in baking dish.
Toss bread crumbs in melted butter and sprinkle evenly over casserole. Bake for 25-30 minutes or until golden brown. Let stand for 10 minutes before serving.