"B" could be either Business or Bypass. My guess is that here it would be "Business:". If it were a new route, rather than a redesignation of the old alignment, I'd put it down as "Bypass", as we did with US 85B in Williston.
Still unclear whether 22B is signed, as such or as Business ND 22. Just to keep the bypassed mileage in our system, I'd err on the side of leaving it in as Business ND 22, which we can fix later if we find it has no route signage.