As with every plant in the entire WORLD, all do best when not overwatered or underwatered. Unless winter is a particular plant's season of growth, it's only normal that their use of water will lessen with lower temps, because chemical reaction rates slow, resulting in less need for water, nutrients, air. (This, given that other factors remain the same.) However, one may find that if relative humidity is drastically reduced, evapotranspiration by the plant and especially direct evaporation from the soil surface increases, somewhat offsetting an expected winter watering regime. This is something each person will learn for themselves in their respective home environments.
Grouping plants together to increase humidity is an entirely different matter. That's a good thing. But no, you certainly wouldn't want to keep the soil watered anymore than at warmer temps. For tropical, semitropical and houseplants, cooler temps favor the growth of pathogens that cause root rot, hence it is safer to let cooler soils go drier, between waterings, than in warmer temps.
