Share 'HELP: Mousse as filling for wedding cake'

Good morning all! I have a wedding cake to do in a few weeks and the couple insists on having mousse as a filling for their tiers (3 tier cake). I've not worked with mousse being used as a filling and the cake covered in fondant. I know I do not have  a fridge large enough to keep this cake cold, so how should I handle this? Would a room with air conditioning be enough? Also what about the da…