I was going to say lemon curd too, but how about lime curd for the margarita shooter? And yolk-based orange buttercream in the macarons. You could do creme brulees in demitasse cups or make something with a creme anglaise or pastry cream type layer. Or a more shootable shooter of berries in a shot of creme anglaise?
https://www.seriouseats.com/recipes/2017/11/french-vanilla-buttercream-frosting-recipe.html