Baby shower question...

My mom is mostly planning my baby shower but I definitely have some ideas I’d like to incorporate. First we definitely want to do the books instead of cards, we love that idea! But my wife and I also really love the idea of a diaper raffle... it would help us so much! Buuttttt at the same time we have a registry that has many many items on it that we’d really like. So is it too much to ask for someone to bring a gift off the registry and diapers for the raffle. Ugh I know you can’t expect a gift and not everyone will participate in the raffle... is anyone getting where I’m coming from??