Bridal Shower

My sister is also getting married next year and my mom and I are co-hosting her bridal shower. One of the venues we are considering only allows their caterer so they just sent us their menus. The shower will be at non-meal time and we are guessing it will probably last about two hours. We are inviting approximately fifty people, but we don’t expect all of them to attend because of Covid and distance as her fiancé’s family live about three hours from where her shower will be at. Some of the options we are considering are priced per person like a cheese display with crackers and a nacho bar. Other options like bruschetta, chicken tenders, meatballs, stuffed ravioli, and sliders are priced per twenty-five pieces. We aren’t sure how much of each item we would need. Does anyone have any suggestions on how many pieces we should expect each person to eat?