The Top

My opinions on the best of each type of four star:
Savage units go under the type of unit they would be minus the savage part (e.g. Cannon is under Cavalry)

Infantry-Octavius
Pikeman-Ignatius tied with Achilles
Paviser-Gilles de Rais
Cavalry-Hyacinth
Archer-Robinhood (well, William Tell and Anatole are both bad...)
Mounted Archer-
Musketeer-Sarky tied with Terim
Arbalist-Alash
Mage-Merlin