Would love to try all of the above. Haven't met the people to do it with sadly. But it is something that I want to try.
I would have accept the invite and see where things go. As a third having the wife watch as her husband sucked me was a lot more erotic than I ever thought.
For me it would be erotic to have the wifes pussy engulf my cock while her husband watched or she sucked him off.
Our last threesome was just the opposite. Our friend had his cock buried balls deep in my wife's pussy, while she vigorously sucked me! Watch his cock plunge into her while she Hoover'd me was AMAZING!