Yes; Mexican and American laws allow for a person to hold dual citizenship.
yes.
If they are an adult their status is still the same, they are an illegal alien.
No, she's still a British citizen.
Yes, he is 93 years old and living in California. He is a naturalized U.S. citizen born in England in 1919 and a Christian Scientist.
Well, it depends on what you mean. If you are talking about ethnicity, then yes, they are Mexican. For example, if you are Italian and born in America, you are still Italian. But you are also an American citizen. You can have two different home countries without any problem. Also, there are German-Americans, French-Canadians, etc. Your heritage and your home country can be combined and you still have clear definition of who you are and where your family originates from. Very simple.
No. A baby born in the USA is automatically a citizen, but the mother is still illegal.
She will still need to be sponsored by the spouse (who is an American Citizen) and apply for residency first. Once permanent residency is granted, she has to wait (I believe it's approximately two years) to apply for citizenship.
You are a natural born citizen of the United States if you were born in territory belonging to the United States. You can still be a naturalized U.S. citizen if you weren't born in the U.S by going through legal procedures, but you can never be a natural born citizen unless you born as one. The Supreme Court has never ruled on the exact meaning of the phrase "natural born" which appears is the US Constitution as a requirement for the US president. Persons born in foreign countries with two US citizens as parents are US citizens but it is not known whether they are legally natural born.
No, US laws state you can only be an American citizen.
By making an official application at a Mexican Consulate in Canada. I know of no foreign born non-Latino that has acquired Mexican citizenship. Maybe this person meant to say "resident status"? Not citizenship. I am a Mexican citizen with a "green card." I know that virtually any foreigner can become a permanent resident in Mexico (I wish immigration laws were that easy in the US!) Citizenship, however, may be a little more complicated. 1st of all you'll need to complete residence in Mexico, This is done with an FM2. Every year you need it approved by Immigration for 5 years. On the 6th year your will receive your last stamp from Immigration Dept. which makes you and permanent resident. Then you may apply for ciitzenship with SRE (Secretary of Exterior Relations)in Mexico. Then you must wait 6-8 months while they review your case and decide if you will receive citizenship or not.
The process is called "naturalization" - the legal process by which a foreign immigrant gains citizen status, and (almost) all rights and privileges thereof. Naturalized citizens still cannot be President or Vice President.
If you were born as an American citizen, yes.