In modern American usage, the
predominant meaning of "half and half" is the one involving 50%
milk and 50%
cream (they're usually
homogenized). The other beverages listed here are almost certainly
allusions to the original. Also note that unlike the others, half-and-half is rarely considered a drink; it's added to
coffee,
tea, or other beverages when something lighter than cream is desired.
Finally, note that this means
calorically lighter.
Ironically, the "heaver" a given
volume of a milk/cream
mixture gets due to cream content, the lighter its
weight.