mulatos and consanguinity

I just received today two copies of the marriage certificates of my great grandparents (from 1822 and 1797). I discovered that one couple were mulatos libres and another couple was mulato libre and espanola viuda and gives the name of the former husband instead of the names of her parents. One of these couples were related by fourth degree of consanguinity.

Was a mulato the offspring of Black and a Spanish?

Was an espanol someone who was born in Spain or is it possible that she was a criolla? I am trying to find her place of birth.

Is fourth degree of consanguinity a first cousin, offspring of our tios?

Rosie Cordova