Straight Edge Society
Straight Edge Saviour
Tim's said it quite a bit on Twitter that he isn't a big drinker. Not sure what reason he'd have to lie about it. Jade, Tim and Tahan all drank a bit in the house despite saying they aren't really drinkers. A lot of people who I know say they "don't drink" but it doesn't mean they never drink or they have a massive aversion to alcohol, just that they aren't big drinkers.
I think you phrased it more accurately. "They aren't big drinkers", not they are "non drinkers" because that implies they completely abstain. Clearly they are drinkers, but not Boog/Ed/Tully level drinkers. They enjoy the occasional drink or night of drinking. Or maybe more, who really knows?