One coffee a day is NO problem on most all the protocols I recommend, but hold the sugar. Stevia or Xylitol are OK.
Kombucha? I'd go for kefir instead to be honest. Try some straight lemon juice the the morning, it makes the tongue growth quite p****d, and can clear a tongue fungus rather quickly. Try brushing the tongue with your toothbrush too, it helps to stimulate the GI tract.
Small health improvements daily pay big dividends in time.