Yes
You can, but it wouldn't be advisable. The illegal alien can be deported at any time. It may even be impossible for them to get back to the US.
You must take a years break.
Yes You can so long as you were divorced some where.
Elisabeth Taylor did it three times.
not really because the illegal alien must have to go through "naturalization" and must wait a few years while living in the united states like 7 years.
Not legally since you never actually divorced him
He came as an illegal alien and spent several years legalizing his status.
Can an illegal alien who was deported and barred for ten years come back sooner by marrying an us citizen?
An illegal alien can become legal by filing documents with the INS. If the person can prove they have been here 17 years and never been in trouble, it could help them receive papers faster.
You never have to get divorced. But if you have been separated for that long, and don't intend to ever resume the marriage, it's a smart idea.
You do not need an anulment to remarry, you just need to be divorced. An anullment is a legal process by which the court deems the marriage to never have happened. Many people get an anulment for religious reasons but the majority of marriages end in just a divorce and not an anulment as well.
No. "Separated" is not "divorced". The married man is still married and must obtain a legal dissolution of the marriage before he can remarry. In most places, marrying a second person while still married is called bigamy, and it is a crime.