so...
Maiden in Black: The "Go home, you're drunk" girl
Anastacia : The non-drinker of the bunch
Herald : The sophisticated drinker (Is that a wine?)
Doll : The casual drinker
Keeper : Old timey drinker

...And Siegward, the Jolly Drinker!

Seems like the Fire Keeper is a first timer if she can't recognize the booze

White wine, red wine, beer, sake, siegbräu.

The obvious next question, of course, is what would Melina drink.