Bar Mitzvah Kiddush Advice

I’m looking for some Bar Mitzvah planning/etiquette help– Our son’s Bar Mitzvah will be a morning service with an evening party later on. Our synagogue has a standard, very basic Kiddush on Saturday mornings with just bagels and cream cheese, cookies, and coffee. I looked into the options for an upgraded luncheon with a caterer, and I was kind of shocked by the prices. The lowest-cost option would run us a few grand, and all it would add is a greater variety of bagels with tuna, some fruit and veggies, and sodas, plus the tablecloths and pretty plasticware. The party that evening will have a fully catered dinner that’s already costing us most of our budget. Would just sticking with the shul’s standard bagel-and-cream-cheese option be too little, since it is lunchtime and we’re not feeding our guests again until 7 pm? What did you all do for your events, or what have you experienced at other people’s Bar Mitzvahs? This is our oldest child’s first Bar Mitzvah season, so we are going into it sort of blind!