Cook fettuccine according to package directions. Meanwhile, in a large skillet, saute mushrooms in 1 tablespoon oil and 1 tablespoon butter in batches until tender; remove and keep warm. In the same skillet, saute zucchini and peas in 1 tablespoon oil until crisp-tender; remove and set aside.
Pat scallops dry with paper towels; sprinkle with 1/4 teaspoon salt and 1/8 teaspoon pepper. In the same skillet, heat remaining oil over medium-high heat. Add scallops; cook for 1-2 minutes on each side or until golden brown and firm. Remove and keep warm.
Drain fettuccine; return to skillet. Add the vegetable mixture, green onions, lemon juice, zest, and remaining salt and pepper; heat through. Serve with scallops.