First, I can't urge you strongly enough to drop the pancakes and serve muffins instead.
Pancakes take a LOT of griddle space, are hard and rather messy to eat, require knives and forks and fixings and don't reheat well. People really like muffins, they can be made ahead and frozen, they are easy to eat and do not require a knife and fork.
Second, with 800 people, even allowing 2 hours, you need 8 lines or 4 two-sided lines. If you serve less than 2 hours, you need even more lines (another reason to skip the pancakes).
pancakes, go for muffins as noted above
sausage, 2 pieces or links per person
eggs, see plan for 100 table- breakfast planning
bananas, grapes, watermelon, see fruit tray page
bagels, only 1/2 per person if you have muffins, You need cream cheese, 1 ounce per person, and jelly or jam 1 ounce per person
juice, coffee and water. See beverage planning page.
Good luck. Write back if I can help further. I am very serious about skipping the pancakes.