No they do not automatically become a US Citizen. They would have to get a spouse's visa and then a marriage based Green Card. After the elapse of time - usually 5 years, they may then apply for US...
Yes. When a non-citizen marries a U.S. citizen, s/he can then apply for US permanent residency. It is important to note that you cannot marry someone solely to obtain a green card as that is...
Yes, they can marry where ever they wish. However, there are immigration laws that regulate if the Canadian can leave the US after their marriage. Re-Entry visa MUST be obtained BEFORE leaving the US...
Yes, but they have to apply for and receive US immigration permission .
Answer.
Do not work until you have your Employment Authorization Card. You can get one by filing the I-765, which you should...