Is there anybody on here that can explain more about the Mexican custom of having "padrinos" to sponsor certain items or parts of a wedding?

Basically, they are there to help you & guide you. The Padrinos have to be a couple that you admire & look up to. They help with the cake, ceremony jewelry, venue etc.

The Padrino is equivallent to the godfather in some cultures... In the Christian wedding it is essential to have a padrino!