If you feel that the humidity is low, go ahead & mist or provide a humid hide. This time of year I seldom worry about it. My snakes seldom have trouble shedding "as is" and if they do I deal with it then.
As for feeding: Most of my snakes will feed while in shed. A few will not. Some eat, but very slowly. I don't usually offer my larger snaked food while blue...they just don't need it. My smaller, younger snakes get a chance to let me know what they want. I have learned not to bother some & to continue feeding others (although, as mentioned, they don't need really). Some will tell you that feeding while in shed may lead to an increased probability or regurge. This has not happened to me ever. I do make it a point not to offer large meals when blue. Actually, now I usually don't bother thawing food out for my "blue" snakes...but they may be offered leftovers or given food if I didn't check first to see why they were hiding.