Your guests! What do they like? Any special dietary needs? Cones or cups or both? Sugar free ice cream? Sherbert? Gelato? How about toppings: cherries, nuts (beware of nut allergies!), cherries?
Special considerations include whether or not anyone invited is lactose intolerant and having fruit based sherbet or soy based dairy alternatives for them. Have a means to clean up clothing of melted ice cream.
Ice cream melts. It's not the greatest choice for an outdoor party unless you have a way of keeping it cold. Outside of that, have at least two flavors and it's nice to have toppings.
