You make some interesting points.
To me it's all heading in one direction, but may take a little while to get there.
But I don't agree with Jazz being able to revert to a 9 role when required, if he became starting lock.
what's needed...
Simpkin to back up his breakthrough performance and show he can perform consistently
Jazz to do the same as lock (no reason he can't)
and Navale to adapt to NRL speed and (by July or so) be capable of decent minutes.
If that all happens ... Jazz start at lock, Simpkin hooker, Jake to prop, Crokes, when (if ever) ready, to bench utility (I reckon Croker has many of the qualities of Cam McInnes)
By September a bench featuring Bull Crokes and Navale would give us a decent shot!