How will an SEC lawsuit affect my EB-5 visa eligibility?

Much more information would be needed for me to give you an opinion. It can go either way depending on the specifics of the case. Please consult personally with an immigration attorney.

Civil court matters typically do not affect eligibility or admissibility for lawful permanent residence. USCIS will look very closely at the case to determine if it affects your lawful source of funds or not. As long as you do not have any criminal convictions and you have not committed fraud against the U.S. government in connection with any immigration application, your case should be allowed to go forward. Since this is a fairly complex and unique situation, you should seek experienced immigration counsel to represent you.

While it may not stop your EB-5 application, it will likely come up in the application reviewing process. The general rule is you must disclose it and explain all the facts, otherwise your application will be denied. Do not hide anything. If questions arise, you will be given ample opportunity to explain your position.

It does not per se exclude you from applying, but you should mention it and submit your explanation to prevent a possible RFE in the future.

It depends on many things. Generally, for applying for visas, USCIS or the Department of State does not look favorably on any matters of fraud, but the specific nature of your case will be the deciding factor on any future visa processes.

If it is a civil matter, under current rules you should be admissible to the United States.

It would depend on what the allegations were and the terms of the settlement. If there were any allegations of investment fraud, then you may have a moral turpitude issue.

You are an investor, not a program seeking investments. I do not see how a SEC lawsuit would adversely affect you, unless, of course, it involved some prior EB-5-related project/regional center/investment. You should definitely seek out immigration counsel.

Much will depend on whether your SEC matter involves an issue of dishonesty. You should speak off-line with a securities enforcement attorney or your own counsel (hopefully you had one).