I tried this out and it was fun, but weird at the same time. I did Wanderer's Palace as a Samurai with Gladiator, Arcanist & White Mage NPCs. I had a smooth run until King Tonberry with the same issue as everyone. Almost killed it, but died anyways. I abandoned and took them to Stone Vigil and that was a lot better. At the final boss they kept standing in the ice path, because they kept following the boss and ended up wiping. I then figured to use the disengage when it flies and that worked. They follow me away from AOEs, then re-engage and we beat it easily. I might have to give it a go as a tank and the try healer and see how that goes. Tank feels like that might be the way to go through this, though.