I think Craig is telling a bit of a fib there, Ola and James were told they were not needed as neither of their celebs had signed up for the tour. The production was really struggling to get past contestants to join, Robbie changed his mind so a female pro was needed, Katya was asked as it wasn't thought that Ola would tour without James. Holly also turned the gig down as it wasn't her thing apparently.
I have this information as I know the team promoting this event as it is a BBC Worldwide Production, the same company I work for, although not in that department. It will be interesting to see who Craig employs on the Pro tour later in the year (another Worldwide Production) as I think that choice is down to him.