Cook the pasta according to package instructions until al dente. Drain and rinse under cold water to stop the cooking process. Transfer the cooked pasta to a large mixing bowl.
Season your shrimp with the onion powder, garlic powder, and 1½ teaspoon of Old Bay.
In a medium-sized skillet, melt your butter. Once your butter is melted, toss in your shrimp and minced garlic and cook until your shrimp is done cooking. This should only take 2-3 minutes.
Dump your shrimp in the same bowl as the macaroni noodles and put it in the fridge to cool.
Dice up your onions, bell peppers, green onion, and imitation crab meat.
Once your shrimp and noodles are cooled down, add in your vegetables, imitation crab meat, and salmon.
Then, add in all of your dressing ingredients and the remaining 1½ tsp of Old Bay.
Mix everything until it is well combined. Give it a taste test and add any salt, pepper, or more Old Bay seasoning according to taste.
Serve immediately, or cover and refrigerate for at least 1 hour to allow the flavors to meld together before serving chilled. Enjoy your creamy seafood pasta salad!