Yes, you do need a greencard to live in the States of America.
No, Certainly not.
How you can get greencard if you work with visa J1?"
Depends how much money they have but for this you would need millions.
Yes, but you need unexpired Passport from country of origin also.
You can get a greencard if a US citizen familiy member, relative or fiancee petition you.
greencard holder gets a fellony does he get deported
You have a strong enough argument to take action. Contact the people who issued the greencard.
yes.
Person who has become lawful permanent resident after marriage but was not able to take spouse along to US, this immigration Form I-824 follow to join application can be used. In this case a separate Form I-130, Petition for Alien Relative need not be filed instead US consulate just needs to be informed that as you are a lawful permanent resident and apply for immigrant visa for your spouse. Your spouse need not wait any further for availability of a visa number. Similarly if you had children before you became a green card holder they also may apply to join you.
You do not need a transit visa, if you do not go out of the airport to see London or change airports at London.
You do need a Green Card to work in the US. The best places to contact are Homeland Security and USCIS as they will offer you the information you need, and what you will require in order to apply for one.