Help Me Build a Gluten-Free, Dairy-Free Celebration Cake

I’m planning a celebration cake that needs to be gluten-free and dairy-free. I’m considering vanilla or chocolate cake with a berry filling, but I’m unsure which frosting will taste good and stay firm. If you’ve made something similar, could you share your favorite cake, filling, and frosting combination? Eggs are fine, but everything else must be gluten-free and dairy-free. I’d also appreciate tips for preventing the filling from leaking. Thank you!