It's going to be Morrison I think. I'm 99% sure it'll be him. I wouldn't be unhappy with that choice. I'd not be disappointed with Naylor either who seems to have that ability to get a team to play above itself - a skill that few coaches have. My only reservation with him is his lack of experience but then Morrison is relatively new too.
Harris - No he could put a glass eye to sleep. McDermott or Anderson - doubt they'd be applying since they have jobs.
Brian Smith? Possibly. Ideally I'd have him working with Morrison or Naylor rather like Smith did with Elliott back in 95/96. Smith could take over a backroom role looking at recruitment too - perhaps relieving Steve Ferres of that part of his job. I would expect a dual recruitment would be too costly so won't happen but I think this would be my "in an ideal world" solution. Smith could also advise Robbie in the role of being a chief exec. Robbie is one of his proteges after all...