Thank you for thinking that you have talent and that soon, very soon, you will be discovered. They say who and how many get invited. They will invite their friends so that their friends can see that they managed to raise you into respectable adult and that they are rich enough to afford the lavish ceremony. The couple may invite some of their friends if there is any room left. And why shouldn't the ceremony be for the parents - they are paying for the damn thing.
Gift registries are the most obscene instances of consumeristic greed.
More than likely, you've moved out of your parent's place so you have all the stuff that used to be given as gifts. If you are getting married soon, please don't invite me. The only positive aspects of weddings is that you get to watch people get embarassingly drunk. But even that isn't all that satisfying because you don't know them and won't be able to bring up the subject of their behaviour with them later. In a function in a .js file, not fine.