yes they can do that
Doesn't matter if you have a green card. It depends on your nationality.
No
No - you need a passport too.
puerto ricans do not have to have a green card to enter or work all they need is a passport and they will be fine puerto ricans do not have to have a green card to enter or work all they need is a passport and they will be fine
Having a "green card" from the United States will allow you to enter the US if you leave. It has nothing to do with access to other countries. Whether or not you will need a visa to travel to New Zealand depends on the country from which you have your passport.
No, it is not mandatory for green card holders to posses a machine readable passport (as the green card is machine readable).
That is allowable.
No they cannot. You must be a US citizen to enter.
A Canadian citizen with a green card can use their Canadian passport to exit the US and use their US green card to re-enter the US under the same status. Hope this helps.
Yes provided that relative is a permanent resident or green card holder or a US citizen. Once they petition for relative depending on the eligibility and availability of visa the relative would be issued a immigrant visa to enter US after which will be issued green card.
It is possible to get a Green Card even if you have entered illegally. Since you are on a valid visa now, it will help you get the green card. The illegal stay in the US may affect the Green card application process to some extent which depends on how long you were illegally staying in the US.