Usually, the roots remaining on an iris rhizome won't grow anyway - the plant will put out new ones once it's planted. When I dig iris, I usually leave on a few inches of roots just to help keep the plant from falling over when replanted (I trim foliage down to 4-5 inches for the same reason). I bet these will grow, but given their small size I'd get them in the ground as soon as possible (particularly given your zone - you want to get them in the ground at least six weeks before your first freeze, so they have a chance to establish before the cold weather sets in.

A bleach solution dip is a good way to prevent the spread of pathogens - 1:9 or 1:10 bleach to water is the generally accepted ratio. Don't leave them in the bath too long - 20 minutes is fine. Rinse thoroughly with water afterward.