Of these, the bonuses that can scale do so as the hireling increases in level.
Melee hirelings use the defensive package equal to their level.
Rogues/bards use the package two levels lower.
Clerics/Favored Souls use the package three levels lower.
Sorcerers/Wizards use the package four levels lower.
As an example of how the stats scale:
Light Fortification from levels 1-5, Moderate from levels 6-10, and Heavy on 11+.
So a melee hireling gets Heavy Fortification at level 11, while a Sorcerer gains it at level 15.