I would feel that they should all get a buff from boss, personally I would have all 5 commandos on the field so with 38 buffing them all would be useful.
Maybe an ability like a speed increase appears on 38 when ever a friendly ally is defeated
Also thought of Scorch having an passive buff that increases his defence for each living clone ally, that might make him more survivable.
Still not sure on the leader abilities though, feel gregor would have something to do with damage maybe and 38 with defense, speed and maybe some turn removal. Or something like that which would encourage either characters to be useful