Explain the day to everyone who's coming
A baby naming ceremony brings grandparents, new parents, and cousins into one room, and not all of them know what a naming day involves. Distant relatives want to understand the order of the ceremony, whether they're expected to do anything, and when they can sit down to eat. The invitation page answers those before anyone phones the parents to ask.
There isn't a naming-ceremony design in the app yet, so you begin from the nearest baby celebration setup and rewrite it in your own words. The general tools are the ones that matter here: a shareable page, replies tracked against names, meal notes so the kitchen can plan, and reminders for whoever forgets to answer.