You can wrote back.

You can expect to have at least 5-6 people in the kitchen and 20+ out front to set up, serve and clean up this function. At LEAST 4 serving lines- 3 double would be better- for this many people in order for everyone to be served in less than 1 hour. Bread/rolls and maybe salad on the tables would be essential, because of he delay serving.

A vegetable dish is never amiss, will cut down on the main course, and is much more interesting than a tossed salad. A casserole such as my Better green bean casserole or the summer squash casserole would be delicious with this. Or roasted mixed veggies.

If I were doing a green salad, I would probably do a specialty salad such as spinach with blueberries and slivered almonds, or a Caesar salad, or a Greek salad

For a wedding reception you need an appetizer table (or in the case of 400 guests, 4 appetizer tables) with 3-4 appetizers and punch (can be 2 punches, one alcoholic and one non-alcoholic) as well as the dinner, since the guests will wait an hour or more after the service while the bridal party does photographs, etc. This is especially important if there are children among the guests. Fruit trays are always a good choice here.