Heat a drizzle of olive oil in a large saute pan over medium heat. Add zucchini and season with salt and pepper. Cook, stirring occasionally, until golden brown and soft, 4-6 minutes. Transfer to a medium bowl. Add another drizzle of olive oil and add mushrooms and cook, stirring occasionally, until golden brown and slightly crisp, 5-7 minutes. Turn off heat; season with salt and pepper, then transfer to the bowl with the zucchini. Wipe out pan.
Heat 1 tbsp butter and a drizzle olive oil into the saute pan over medium heat. Add tomatoes and season with salt and pepper, and Italian seasoning. Cook and stir until tomatoes are softened, 2-4 minutes. Stir in half the green onion and juice from half the lemon. Reduce heat to low, stir in stock and ¼ c reserved pasta water. Whisk in cream, season with salt and pepper.
Add zucchini, mushrooms and drained pasta to pan with sauce. Stir in 1 Tbsp butter until melted. If necessary add more preserved pasta water a splash at a time until pasta is coated win a creamy sauce.
Divide among plates and sprinkle with parmesan cheese and remaining green onion. Garnish with the remaining lemon wedges.