Please consider an alternative to the spaghetti such as ravioli in sauce or baked spaghetti.
You need about 150 servings of lasagna, cut into 180, as almost everyone will take some. About 1/4 should be vegetarian.
For all the extras, see the spaghetti dinner for 50-60 on the spaghetti page, do 3 times the amounts.
You need an appetizer table with punch to entertain/feed guests (especially if kids are attending) for the hour while you do pictures, etc. With the Italian menu, you could do antipasto platters, and fruit trays.