Ah, Well why you may ask...
Let see to the preview picture one more time, shall we...
...But All of them use Swords?
Yes...However, ALL OF THEM USE DIFFERENT SHIELD. Rectangular and Oval variant, with different Textures, 3 Texture Design each...works perhaps like Sashimono in Shogun 2, where different clan has different Mon Texture...
Remember that shields are classified as Equiments in Warscape engine, just like Weapons.
Now...why Jack Lusted said between Axes and Clubs...Rather than Sword and Hatchets or any others? Since Animation-wise they are wielded in the same fashion. Jack Lusted can say "Maybe" since THE EQUIPMENT VARIETY SYSTEM ALREADY EXISTS IN R2TW, only they are reluctant to use it further than for shield variety; to use it for weapon variety, since shared animation may look weird or awkward...Remember Shared Animation between Nodachi Sword and Tetsubo Club in S2TW?
CA will not make it effect stats, I believe...too complicated. Thats why only equipments that have similar effects will be paired.