I would highly suggest freezing each component separately to keep everything super fresh! You can bake the cake layers a month in advance if kept in the freezer. Be sure to wrap each individual layer tightly with plastic wrap, then wrap in a layer of aluminum foil, and keep it in a freezer bag. For the lemon curd and frosting, store them separately in airtight containers in the freezer, and defrost them in the fridge for a day. Stir the lemon curd and re-whip the frosting before assembling the cake.