For the Hibiscus Cherry Soda: In a small pot, combine cherries, coconut sugar, and vanilla bean seeds (or extract). Mash cherries with a fork or muddler until pulpy. Add water. Bring to a boil over high heat, stirring often, for about 5 minutes.
Remove from heat and add the dried hibiscus flowers. Cover and let steep for 30 minutes. Strain the mixture through a fine-mesh strainer, discarding the solids (and pits).
Stir in the lemon juice. Chill the soda completely in the refrigerator, about 30 minutes. This syrup can be stored in the fridge for up to a week.
To make the Floats: Add 2-4 scoops of vanilla bean coconut ice cream to each serving glass.
Pour about 1/3 cup of the chilled hibiscus cherry soda over the ice cream.
Top with 3/4 cup of high-quality ginger beer. If using, add 1-2 tablespoons of bourbon or coconut rum.
Garnish with a fresh cherry and enjoy immediately!