I would probably have suggested something pretty neutral considering your penchant for water and not a lot of Soda.

Gin and Cranberry is good (can bury a double at the least in cranberry juice and won't taste it, stick to something like Gordon's or Bombay Sapphire for ease of obtaining and drinking).

Some stout can very much carry a coffee flavour, they're certainly not sweet or too gassy (Guinness doesn't taste that much like Coffee but if you can get it in America, a bit of Youngs "London Stout" is good and very strong coffee flavour).

light beer, add in a wedge of lime if it's something like Corona. If you don't have lime, use any citrus but for the love of god, put something in it.