Agnosticism is the "religion" in which I believe in. I know that there is something spiritual but I don't believe it's God. This something is there to protect us and it doesn't really matter what it is :)
Everyone can believe in everything which make them happy and secure. It doesn't matter if this will be God or something else. The meaning of believing is just to feel better in this world :)
In my opinion it doesn't matter what is your religion the size of the wedding has to be normal and comfortable for you. I think the best size in not too much people just the closest ones :)