Yes you can.
Charles Chaplin never became a US citizen.
He became an American citizen in 1940
Jackie is not a US Citizen.
yes. as of 2004, he became an American citizen
Yes. If their mother or father became a US. citizen then legally if they're under 18 they are a citizen.
US and UK allow Dual citizenship. A person can be a US citizen and a citizen of UK if he/she desires to. But if a person applies to get naturalized as a citizen of UK when he/she is already a US citizen, then it will lead to losing US citizenship.So a person can have US & UK citizenship as long he/she is not a naturalized citizen of UK.
The info I have on him doesn't state he became a citizen, so it is possible he didn't.
because he wants to complete his experiments in us
No- the president must be a native-born US citizen.
albert eintstein
In my experience, it would depend on how much US residency the man has and what date he became a US citizen. Children of US citizens are eligible to derive citizenship from their US citizen parents (jus sanguinis), but the citizen parent must meet age and residency requirements.
Albert Einstein - see wikipedia entry for confirmation.