Do not use Cedar with your rodent, use either use pine or pine pellet or any other safe substrate such as aspen etc.

Remember that mites are host specific, wood mites will not affect your rodents in any manner.

I would also be very cautious using seven dust with your feeders.

Not sure why you have outbreaks but I can tell you that I never had any mites from wood shaving nor the feed, if you have mites from your bedding than it is time to change supplier in my opinion.