Yes, you should be able to raise it to adulthood. But again, if you want major males, try providing more wood, meaning "less fermented substrate" or actual wood pieces.
It's been said that majors are achieved by allowing the larvae to chew on buried (decayed) wood pieces. Some also have had success with raising them on less decayed wood flakes. More wood, less soil seems to be key.
It's normal and there isn't really any way to get rid of them completely. You can use a soft brush to lightly brush them off and/or carefully rinse the larvae under running water. But, the mites are normal and will almost always be present.