Combine first 5 ingredients in medium saucepan on medium-high. Bring to a boil. Reduce heat to medium. Simmer, uncovered, for 3 minutes until shrimp is pink. Do not drain. Remove seafood to small bowl using slotted spoon. Cover. Keep warm.
Add garlic, zucchini, broccoli and mushrooms to liquid in saucepan. Bring to a boil. Reduce heat to medium. Cover. Simmer for 3 minutes.
Add red pepper, green onion, tomato and pesto. Bring to a boil. Reduce heat. Cover. Simmer for 3 minutes.
Stir evaporated milk into flour in small bowl until smooth. Stir into vegetable mixture until boiling and thickened. Gently stir in shrimp and scallops until heated through.