In married families (i.e., households or "spouse and kids"), Margot and Carlos are generally called things like "Honey", "Darling", etc. by their spouses, and "Mommy" or "Mom" and "Papa" or "Dad" by their kids (depending on those kids' ages).
In found family, again, people usually use the same name. (Indeed, willingness to call someone what they want to be called is a good criterion for allowing someone to be part of your found family.) 3/3