None of those things would harm a Hussein candidacy. They would only render the man virtuous in Democrat eyes. So far he is too clean to be a credible Democrat.
That's wishful thinking on your part. Even if it wouldn't sink Obama in getting the nomination, a PROVEN homosexual relationship would be DEVASTATING in the general election. Plenty of people (blacks are especially anti-homosexual) who might otherwise support Obama are not ready for a queer POTUS. Perhaps the effect of an interracial relationship is more problematic, but even there, among the ordinarily Democratic working classes in the Rust Belt North, and in the South generally, there are lots of people who don't much cotton to miscegenation. It would KILL him with black women and white men.
Remember, a Democrat cannot afford to lose ANY of their core voters and has to have a reasonable margin among the independents to have a shot at winning, even today. Either of these things would cost Obama (I speculate) between 15-25% of voters who otherwise would support him, and would certainly not help him among a significant number of independents or Republicans (except, if it were homosexual, perhaps among the Log Cabin 'Pubbies, who are no large number to begin with).