So the plan is to get everyone to C in Axes > Brigand for deathblow > Pegasus/Wyvern rider > Falcon Knight/Wyvern Lord?
These three classes have insane growths and movement, why even bother with other classes besides one or two supportive mages? You can shift to Pegasus if low on Spd growths and Wyvern if low on Str.
There is almost no penalty for doing this other than the early low hit rates of units with no Axe experience. It's fun to play but I think I'll be waiting on lunatic before I start another playthrough.