Chicken - 90 lbs (will be cut into pieces in a pretty substantial cream and mushroom sauce)
Mashed potatoes (using your freezable recipe) - 96 lbs
A vegetarian option (I saw that you recommended vegetarian meatballs - how many pounds?)
A cold side vegetable (how many pounds?)
3 different salads totaling 40 lbs
bread rolls - 24 lbs
butter - 6 lbs

And for appetizers:
Veggies for trays: 16lbs
Dip - 16 cups??
Crackers - 12 lbs
Cheeses - 16 lbs
Olives - 6 lbs
Chips - 16lbs
Hummus - 2 gallons

Drinks:
One bottled soft drink per person
Punch - 12 gallons
tea - 60 bags
4 lbs sugar
4 quarts milk
honey
sweetener
Coffee - this is where I had a question. I have down 3 lbs regular and 1 lb decaf, but will people drink that much in the evening?

We will also have cake and possibly ice cream.

I think this is too much food, because if I should plan for 1.5 lbs per person, I end up with about 70 lbs too much (and this isn't even counting the sauce for the chicken or the other ingredients in the potatoes or the cake). So what should I trim down?

3 serving lines or 2 double sided, 2 appetizer areas

Chicken - 90 lbs (will be cut into pieces in a pretty substantial cream and mushroom sauce); 80 OK
Mashed potatoes (using your freezable recipe) - 96 lbs-OK
A vegetarian option (I saw that you recommended vegetarian meatballs - how many pounds?), For 200 people, about 12 servings- 4- pounds
A cold side vegetable (how many pounds?) Roasted veg, dome ahead and served Italian style at room temp? 28 pounds ready to cook per 100
3 different salads totaling 40 lbs ??? Do any green salad per 200 using the plan for 100 list. Specialty, 2 gallons per 100
bread rolls - 24 lbs- ok
butter - 6 lbs- ok

And for appetizers:
Veggies for trays: 16lbs; 1 pound per 10
Dip - 16 cups?? less if this
Crackers - 12 lbsOK
Cheeses - 16 lbs OK, some can be spreads or logs
Olives - 6 lbs, at least 1 1/2 gallons
Chips - 16lbs-OK, dont open all at first
Hummus - 2 gallons; could do salsa or other dip for part?

Drinks:
One bottled soft drink per person-OK, not red
Punch - 12 gallons-PK
tea - 60 bags- iced tea>? 12 gallons. 3-4 not sweet
4 lbs sugar
4 quarts milk? If for hot beverages, do 1/2 and 1/2
honey
sweetener, not equal
Coffee - this is where I had a question. I have down 3 lbs regular and 1 lb decaf, but will people drink that much in the evening? I would do 2 decaf, 2 reg and get real half and half

We will also have cake and possibly ice cream.
Suggest you skip the ice cream, challenging to store and serve.