C.R.
We had my daughter's baptism at Wayfarer's Chapel (aka the glass chapel) in Rancho Palos Verdes. It is QUITE a drive but truly one of the most beautiful locations in California. The service was nondenominational and welcomed my daughter as a child of God. We met with the pastor before the ceremony and he explained their beliefs that children are not born in sin and that the ceremony is about welcoming and celebrating the child as one of God's.
Here is a link to the website: http://www.wayfarerschapel.org/
Here is the link to the baptism information: http://www.wayfarerschapel.org/services/baptism-services/
The pictures on the site don't even do it justice. I know you mentioned wanting to have your ceremony on the beach but this chapel does overlook the water. If nothing more, you, your hubby and daughters should take a road trip one day to see it in person. It really is amazing.