Mestizos are not "White Hispanics."

Mestizo refers to someone who is part white, part Native American/indigenous usually half. (In Latin America the term "indigenous" refer to the descendents of the native people.) Example include Mercedes Sosa, Lila Downs, Benjamin Bratt and Ritchie Valens among millions of others. The correct word to refer to a White Latin American is "Criollo." Examples of famous Criollos are Luis Miguel and Shakira. I don't know about Ryan Cabrera but most likely Christina Aguilera is a Castiza half mestizo, half white which I'm almost certain Jessica Alba is.

Mestizo is known even by people outside of Latin America and is still in everyday use. Criollo is a very old word and is rarely used but it can still apply to people who are entirely white like Shakira and Luis Miguel.The reason Christina Aguilera is most likely not white is because the overwhelming majority of Ecuadorians do not identify themselves as being white so it is unlikely her biological father is.

Finally, most Mestizos are not exactly 50/50 White/Amerindian. I would say that they are more like 75/25 Amerindian/White. That is why their Amerindian features stand out more. Also, when you think of a Mexican Mestizo, what comes to mind? Medium-to-Light Brown skin, Jet-Black hair, Chinky eyes, Short in stature/chinky, stock bodies, features that are COMMON to the Amerindians in Mexico. You also think of as thin lips, fine cheekbones, long narrow nose, and a fine texture of hair, features COMMON to Europeans. One does not imagine kinky hair, thick lips, wide noses, long, lean bodies, and dark Brown skin, features COMMON to africans.