Before spending any money, you should sit down with an attorney to see if your fiance will be admissible or not. For example, if he ever said he is a U.S. citizen or has had any criminal problems, he might not be admissible at all.
If he was here for more than 6 months before he had voluntary departure, then he will have at least a 3 year bar (possibly a ten year bar if he was here for more than 1 year) and will need a waiver. This waiver must prove that if he is not approved, it will cause you extreme hardship.
Typically a fiance visa will get him here a little bit quicker (assuming he is approved) than if you marry him and then petition for him. But if he needs a waiver, it will need to be approved before he can come here.
I recommend finding an attorney who is experienced with this type of case to help you review his options as well as to assess his chances at being approved for a waiver.
The fiance visa, and subsequent spousal petition is usually faster. As to returning to US, yes, there may be a number of bars, for which your fiance may need a waiver. When your fiance took VD and left the country, there should have been documents given indicating how long your fiance was prohibited from making an application. Also, if your fiance was in an unlawful status for longer than 1 year before leaving the country, then there is a 10 year bar as well. Consult with experienced immigration attorney to assist you with the process.
Contact immigration attorney Gintare Grigaite, Esq. at 646-407-2331. Answers on AVVO do not constitute legal advice and do not form attorney-client relationship. Always consult an attorney for a legal advice.
You have so many questions and your potential case (filing for your wife) truly requires that you consult with an experienced attorney.
Even though your fiancee left voluntarily, she still may be barred from re-entering the US for a certain amount of time (3/10 years).
Usually, the fiancee visa is quicker, but that doesn't take into account if you will need to file a waiver or not.
An immigrant visa - the person intends to immigrate/live in the US.
Non-immigrant - the person wants to come to the US temporarily.
Before you file anything you need to consult with an attorney. Make sure that you have your fiancee's immigration documentation for the attorney to review.