I fully agree with your scenario as to why would the get rid of him and for mine your post clearly demonstrates the problem with having Flanno as the go to coach as it means we have to suffer Mc Humptydumpty for another full season and I wouldn't put it past him to do a lot of white anting in an effort to upset the apple cart.
I still think making the 8 is still in play as a target for keeping or ousting McGregor.
If Flanno is our target, it wouldn't surprise, especially if we miss the 8, if the Dragons reapproached the NRL for a reduction, even to the point of 13 games onto the 2021 season. Failing that the next best option as psuedo head coach would be Shepherd. Someone who has no ambition to be a head coach (permanently). We know if this were the case Flanno would be in control with the view to the official title in 2022.
All just theorising, innfact Flanno may just up and go at this.seasons end, or they would just appoint Young as it is the Dragons way.