An honest note on the design
There is no separate gender reveal template library on the platform. What works, and works well, is the baby shower setup: it already assumes a celebration centred on a bump, and its wording is easy to steer from shower to reveal. Swap the registry section for a games note or nothing at all, and the page reads exactly like the party you are throwing.
Reveal guests reply the same way shower guests do: on the page, not to a bot, with answers arriving on one tracked list. Reminders go out to whoever has not replied, and if the cake needs nut-free slices, meal choices and allergy notes come back with the yes.