I've never used lobster roaches... so don't know about that.
It is good that the frogs seem to have an appetite. I always feel a white's with no appetite is not a good sign.
Many people have many different philosophies about dusting. I personally use a product called Repashy Calcium Plus, this product has calcium and vitamins. I dust every feeding. Others use a calcium powder every other feeding and vitamin once per week, and others dust with calcium only once per week and vitamin once per week. I feel that as long as thy're getting their calcium at least once per week and a vitamin once per week, that would probably suffice.