no
Talk to a lawyer: you can probably get the marriage annulled.
I'm not a lawyer, but I think it is.
US laws take precedence, therefore if the couple were legally married in the US and legally divorced in the US, then the divorce is valid. If the couple lived together as a couple (engaging in a sexual relationship, sharing mutual finances, etc.) at the time the divorce was pending then the divorce is not valid.
A marriage can be nullified through a legal process known as annulment, which declares that the marriage was never valid. Grounds for annulment may include lack of capacity (such as mental incapacity or underage marriage), fraud, coercion, or the inability to consummate the marriage. Unlike divorce, which ends a valid marriage, annulment treats the marriage as if it never existed. The specific procedures and grounds for annulment can vary by jurisdiction.
In order for a marriage to be valid, the license must be signed by both parties willingly. If no license was signed, there was no marriage in the first place.
no
If the first marriage was never legally terminated (though divorce or annulment), the first marriage is still valid and the second marriage is invalid.
Georgia will recognize a certificate of marriage from Jamaica. The license will not be valid in the US.
If you never applied for and got a marriage license, but got married anyway, then no, the marriage is not valid. And any minister, priest, etc., who performed the ceremony without you having a valid license can get in trouble, although I don't know what the penalty for that would be.
Yes, a marriage in England is valid in the United States.
No, it would not be valid. You really should get the license.
Yes it is valid proof of marriage. The joint agreement is signed by both in the presence of winesses.