I remember trying this once upon a time..possibly for just about every season. It's interesting how originally, Hagman was not thought to be the star, so for the first 2-3 seasons, it very well could have been "starring, Victoria Principal." Then I think It would have become "starring Larry Hagman" starting with the 4th season, and possibly "and Victoria Principal", as that billing is also usually, or sometimes used to bill an actor who is almost in line with, but not quite on par with the actual star. It's a little confusing because sometimes the "and" quite simply just means "lastly".
Dallas would have been a pain in the butt to figure out where everyone would fall into place, especially once more characters were added in the 8th season intro.
It's also hard knowing exactly where to place people like Barbara and Howard Keel because they were Hollywood royalty, but they didn't necessarily have huge parts in the series, at least not compared to the two main couples, and Cliff. So, how do you figure out their places in the credits- based on legacy, or the size/type of the role they are currently playing? This is where I do like the idea of using an "and" as
@Swellin did for Barbara, but I think maybe a "featuring" or "with" would have worked.
