How big is your grill?
Grilling 80 portions of salmon safely will be tricky, but it appears you don't want to go easy.
So, for appys, how about bacon wrapped around jumbo shrimp and a slice of water chestnut, and a spicy/sweet chili dipping sauce. Times 160 (people will want at least 2) I've been craving that, lol.
As far as ice cream goes, you're gonna need about 8 to 10 gallons, plus toppings if so inclined.
The grill is a standard 3 burner Weber - the surface is about 25 x 20. I might be able to cook 20 small (suitable for a roll sized sandwich) portions at a time. and then serve with some arugula or capered mayo or avacado
https://www.foodnetwork.com/recipes/ina-garten/grilled-salmon-sandwiches-recipe-1941492
I need to keep this simple and while the shrimp sounds amazing, that many would be expensive and the prep to wrap them is a little daunting.