Not too hard to obtain based on what I have been able to find. See
https://playnrl.com/media/2371/coach-accreditation-guide-2017-final.pdf. I don't think it has changed much and seems to apply to all levels. I would assume the NRL would also have Governance courses.
There are a number of sports related courses that can be done at uni/college but don't think any of these are essential or prerequisites as none give you actual experience.
I understand ME seems intelligent and has assisted with some minor coaching related to Hooker position and he knows our systems but Head Coach is much more different. As an ex NRL player he would have picked up many tips from the various coaches he had during his career and apply/modify these in developing his method but NRL clubs are professional businesses with pressures from supporters to perform well and unlikely to punt on an inexperienced coach still developing and testing their methods which is generally done as coach in lower grade (results required) or as an assistant to Head Coach.
As much as I like ME, I don't think he is the right person in the current climate to be taking a punt on, and would be low on the list. JM fits the bill perfectly and my choice.
Fan expectations based on past few seasons and our roster (assuming we haven't "shat ourselves and dropped our bundle" over the scandals), are we make top 8 at least, anything more is a bonus and in the lap of the footy gods.