I love florals. I regularly use them in food applications, especially elderflower and lavender.
@Becky suggestion of elderflower is an excellent idea. To me elderflower taste like a lovely combination of honeysuckle and kumquat.
If you live anywhere near a World Market or Whole Foods, both carry Belvoir elderflower products. My Whole Foods in the wine country stocks lightly carbonated elderflower lemonade. World Market stocks both the elderflower lemonade and the elderflower cordial. I prefer to use the cordial, But in a pinch I’ve used the elderflower lemonade.
Other flavor pairings that come to mind are based on classic pairings for honeysuckle teas and iced drinks: peach, melons, and cucumber. While melon and cucumber are problematic in a baking applications, peach is translated well.
A peach cupcake with a honeysuckle buttercream, or an vanilla cupcake with honeysuckle simple syrup and a peach buttercream.
If you wanted to go for warmer, richer flavors, an brown sugar, almond and nutmeg flavored cupcake with honeysuckle buttercream might be a nice flavor combination as well.
I’m thinking a berry like blackberry might pair nicely with honeysuckle as well.
Using a syrup is a good approach. I prefer to use florals in a simple syrup as I feel I it gives me more control. Lavender is the exception, preferring to infuse lavender in sugar instead.
Florals are tricky as they go from a lovely nuanced note to “OMG it taste like a bar of soap” in nothing flat.
Please let us know how it turns out.