when I read this, I also became curious if my water team can do it since I probably have more or less the same assault % that you have, so I assembled a team with the natural 3 SR + atk type and the results were:
obviously took rudra though, but I was surprised that herc and neptune(w/ 10 max stack of her unique buff) could tank that rage trigger with only a water kaiser buff lol
I'm at 8 points now... but I don't think I can do that arthur mission since shes obviously not as tanky as herc is, and I would lose the benefits of having herc's axe
but I guess I can safely say I can at least get 2 ori for this guild order (dont know yet if I can go beyond that though)