Fill a large 1-gallon stock pot with a pasta insert three-quarters full with water. Bring to a boil over high heat and add the salt as it boils. Place the angel hair in the salted water and return to a boil, stirring occasionally. Cook the pasta until nearly al dente, about 8 minutes. Drain and set aside.
While the pasta is cooking, heat a large saute pan over medium-high heat and add the olive oil, sausage and onions and saute, stirring occasionally, until the sausage is lightly caramelized and the onions are translucent. Add the garlic to the pan, and then add the zucchini, bell peppers, tomatoes and thyme. Cook until the vegetables are tender, about 3 minutes. Add the heavy cream to the pan and cook an additional 2 minutes. Add the crawfish and basil. Add the al dente pasta and continue to cook the sauce and pasta, stirring occasionally. Remove from the heat and add the seafood seasoning and Parmesan.