Setting the Time for a Baby Shower at Work?

I'm a co-organizer of a workplace baby shower. The host is my coworker's BFF. We nurses work at a busy hospital and lunchtime is the busiest time taking care of patients and sorting out MD orders after AM rounds. The celebrant insists on coming to lunch (noon). Majority of us coworkers prefer an afternoon shower so at least that's a downtime for us when we can celebrate in a relaxed mode. Besides, if we all chip in $ for a gift card (our goal is $300 minimum), people at our workplace tend to sign up for appetizers and finger food, not lunch which could be pricey. People crash potlucks and if you opt for lunch, the food better be satisfying and be enough for all.

The best friend organizer is firm in agreeing with her BFF celebrant that they want a lunch baby shower. The hostess volunteered to buy decorations. As a co-planner who has had so many hours of experience doing work parties etc., I volunteered to bring mini sandwiches, drinks, ice cream, and pastries. The hostess only signed up for a fruit plate and cookies. This is with the idea that they both want a lunch potluck vs my idea of an afternoon (lighter, cheaper, less imposing on coworkers to bring food to a potluck). While all know the celebrant gets to choose the time of day when to have her shower (ie. her availability), but is it too much to insist on an afternoon shower because all that people would sign up for are appetizers, side dishes, and no main dish so far. People at work tend to graze. The hostess has a stick figure and eats like a bird. It's unnerving that the celebrant and hostess insist on lunch potluck when all the hostess signed up for are cookies and fruit plate. I have signed up for a lot already (more than $100 of my own $$ and I'm just a regular friend at work).

A lunch potluck is super stressful for most of us, prep time typically starts an hour and a half before the event. Do I and the rest of the gang have a say in the time to have the shower? The celebrant is known to be stubborn and maintains that she would like to come at lunchtime. There's no food to serve at lunch! My mini sandwiches are the only substantial food on the sign up sheet. I want to serve it as something to serve in the afternoon. They're not lunch-worthy. Despite this, the 2 BFFs are insistent on doing it at lunch. There's a sense of entitlement that I'm feeling with these 2 younger people (the BFFs) and majority of us are much older. Pls advise.