At the risk of being a bit technical, (as law tends to be) I think reasonable doubt is called the "standard of evidence". Its the phrase "jury trial" that the court found to require unanimous verdicts.
Criminal jury trials have the unanimity requirement. Also, criminal convictions are held the "beyond a reasonable doubt" standard, though there may be collateral actions, or procedural determinations in a criminal trial that have a different standard of evidence.
Otherwise, US States have a lot of flexibility in how they handle non-criminal cases.
Otherwise, US States have a lot of flexibility in how they handle non-criminal cases.